fix: Don't include generator test protos in the API index.

Keep `googleapis` and `googleapis-api-index-generator` separate when generating the API index.

The index generator recurses down the directory structure... which means that test files in the generator's `test` directory are ending up being treated as APIs with a directory path of `gen/test/...`

Fixes https://github.com/googleapis/googleapis-api-index-generator/issues/18

Committer: @jskeet
PiperOrigin-RevId: 387371705

.github/workflows/generate_api_index.yaml

@@ -11,6 +11,8 @@ jobs:
       uses: actions/setup-dotnet@v1.8.0
     - name: Checkout googleapis (this repository)
       uses: actions/checkout@v2
+      with:
+        path: googleapis
     - name: Checkout index generator
       uses: actions/checkout@v2
       with:
@@ -19,10 +21,11 @@ jobs:
     - name: Generate API index
       run: |
         gen/scripts/generate-schema.sh
-        gen/scripts/generate-index.sh $PWD
-        cp gen/tmp/api-index-v1.json $PWD
+        gen/scripts/generate-index.sh $PWD/googleapis
+        cp gen/tmp/api-index-v1.json $PWD/googleapis
     - name: Commit API index
       run: |
+        cd googleapis
         [[ ! $(git diff --exit-code api-index-v1.json) ]] && echo "Nothing to commit." && exit 0
         git config user.name "Google APIs"
         git add api-index-v1.json