fix: accept 4.x protobuf for gapic-generator-python (#1453)

Also update github actions configs and make SHOWCASE and PROTOC global environment variables
This is needed because newest version of grpc already require protobuf 4.x and it makes our showcase tests fail

Author: vam-google

.github/workflows/tests.yaml

@@ -13,6 +13,10 @@ concurrency:
   group: tests-${{ github.head_ref }}
   cancel-in-progress: true
 
+env:
+  SHOWCASE_VERSION: 0.25.0
+  PROTOC_VERSION: 3.20.2
+
 jobs:
   docs:
     # Don't upgrade python version; there's a bug in 3.10 sphinx
@@ -66,8 +70,6 @@ jobs:
           tar -xf showcase-*
           ./gapic-showcase run &
           cd -
-        env:
-          SHOWCASE_VERSION: 0.25.0
       - name: Install nox.
         run: python -m pip install nox
       - name: Install protoc 
@@ -78,8 +80,6 @@ jobs:
             cd /usr/src/protoc/
             unzip protoc-${PROTOC_VERSION}.zip
             sudo ln -s /usr/src/protoc/bin/protoc /usr/local/bin/protoc
-        env:
-          PROTOC_VERSION: 3.19.0
       - name: Run showcase tests.
         run: nox -s ${{ matrix.target }}
   showcase-mtls:
@@ -108,13 +108,13 @@ jobs:
           sudo apt-get install -y curl pandoc unzip gcc
       - name: Install nox.
         run: python -m pip install nox
-      - name: Install protoc 3.19.0.
+      - name: Install protoc.
         run: |
           sudo mkdir -p /usr/src/protoc/
           sudo chown -R ${USER} /usr/src
-          curl --location https://github.com/google/protobuf/releases/download/v3.19.0/protoc-3.19.0-linux-x86_64.zip --output /usr/src/protoc/protoc-3.19.0.zip
+          curl --location https://github.com/google/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-x86_64.zip --output /usr/src/protoc/protoc-${PROTOC_VERSION}.zip
           cd /usr/src/protoc/
-          unzip protoc-3.19.0.zip
+          unzip protoc-${PROTOC_VERSION}.zip
           sudo ln -s /usr/src/protoc/bin/protoc /usr/local/bin/protoc
           cd -
       - name: Run showcase tests.
@@ -127,8 +127,6 @@ jobs:
 
             cd ..
             nox -s ${{ matrix.target }}
-        env:
-          SHOWCASE_VERSION: 0.19.0
   # TODO(yon-mg): add compute unit tests
   showcase-unit:
     strategy:
@@ -147,20 +145,18 @@ jobs:
         run: |
             sudo apt-get update
             sudo apt-get install -y curl pandoc unzip gcc
-      - name: Install protoc 3.19.0.
+      - name: Install protoc.
         run: |
             sudo mkdir -p /usr/src/protoc/
             sudo chown -R ${USER} /usr/src/
-            curl --location https://github.com/google/protobuf/releases/download/v3.19.0/protoc-3.19.0-linux-x86_64.zip --output /usr/src/protoc/protoc-3.19.0.zip
+            curl --location https://github.com/google/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-x86_64.zip --output /usr/src/protoc/protoc-${PROTOC_VERSION}.zip
             cd /usr/src/protoc/
-            unzip protoc-3.19.0.zip
+            unzip protoc-${PROTOC_VERSION}.zip
             sudo ln -s /usr/src/protoc/bin/protoc /usr/local/bin/protoc
       - name: Install nox.
         run: python -m pip install nox
       - name: Run unit tests.
         run: nox -s showcase_unit${{ matrix.variant }}-${{ matrix.python }}
-        env:
-          SHOWCASE_VERSION: 0.19.0
   showcase-unit-add-iam-methods:
     runs-on: ubuntu-latest
     steps:
@@ -174,20 +170,18 @@ jobs:
         run: |
             sudo apt-get update
             sudo apt-get install -y curl pandoc unzip gcc
-      - name: Install protoc 3.19.0.
+      - name: Install protoc.
         run: |
             sudo mkdir -p /usr/src/protoc/
             sudo chown -R ${USER} /usr/src/
-            curl --location https://github.com/google/protobuf/releases/download/v3.19.0/protoc-3.19.0-linux-x86_64.zip --output /usr/src/protoc/protoc-3.19.0.zip
+            curl --location https://github.com/google/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-x86_64.zip --output /usr/src/protoc/protoc-${PROTOC_VERSION}.zip
             cd /usr/src/protoc/
-            unzip protoc-3.19.0.zip
+            unzip protoc-${PROTOC_VERSION}.zip
             sudo ln -s /usr/src/protoc/bin/protoc /usr/local/bin/protoc
       - name: Install nox.
         run: python -m pip install nox
       - name: Run unit tests.
         run: nox -s showcase_unit_add_iam_methods
-        env:
-          SHOWCASE_VERSION: 0.19.0
   showcase-mypy:
     runs-on: ubuntu-latest
     strategy:
@@ -204,20 +198,18 @@ jobs:
         run: |
             sudo apt-get update
             sudo apt-get install -y curl pandoc unzip gcc
-      - name: Install protoc 3.19.0.
+      - name: Install protoc.
         run: |
             sudo mkdir -p /usr/src/protoc/
             sudo chown -R ${USER} /usr/src/
-            curl --location https://github.com/google/protobuf/releases/download/v3.19.0/protoc-3.19.0-linux-x86_64.zip --output /usr/src/protoc/protoc-3.19.0.zip
+            curl --location https://github.com/google/protobuf/releases/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-x86_64.zip --output /usr/src/protoc/protoc-${PROTOC_VERSION}.zip
             cd /usr/src/protoc/
-            unzip protoc-3.19.0.zip
+            unzip protoc-${PROTOC_VERSION}.zip
             sudo ln -s /usr/src/protoc/bin/protoc /usr/local/bin/protoc
       - name: Install nox.
         run: python -m pip install nox
       - name: Typecheck the generated output.
         run: nox -s showcase_mypy${{ matrix.variant }}
-        env:
-          SHOWCASE_VERSION: 0.19.0
   snippetgen:
     runs-on: ubuntu-latest
     steps:

setup.py

@@ -30,7 +30,7 @@
     "googleapis-common-protos >= 1.55.0",
     "grpcio >= 1.24.3",
     "jinja2 >= 2.10",
-    "protobuf >= 3.18.0, <4.0.0dev",
+    "protobuf >= 3.18.0, < 5.0.0dev",
     "pypandoc >= 1.4",
     "PyYAML >= 5.1.1",
     "grpc-google-iam-v1 >= 0.12.4, < 1.0.0dev",