fix: add integration test steps to docs

Author: miraleung

DEVELOPMENT.md

@@ -5,3 +5,7 @@
 - Execute unit tests by running one of the sessions prefixed with `unit-`
   - Example: `nox -s unit-3.8`
 - Lint sources by running `autopep8`.
+
+## Integration Tests
+- Running tests: `bazel test tests/integration:asset`. See the full list of targets in `tests/integration/BUILD.bazel`.
+- Updating golden files: `bazel run tests/integration:asset_update`