Add arduino lint workflow

Author: stnkl

.github/workflows/arduino_lint.yml

@@ -0,0 +1,12 @@
+name: Arduino lint
+
+on: [push, pull_request]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: arduino/arduino-lint-action@v1
+        with:
+          library-manager: update

.github/workflows/build.yml

@@ -1,6 +1,6 @@
 name: Build library
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:

.github/workflows/build_examples.yml

@@ -1,6 +1,6 @@
 name: Build examples
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build: