ci: adjust paths filter for workflows, only look at main.yml (#11572)

Refine the paths filter for workflows from `.github/workflows/**` to
`.github/workflows/main.yml`. This is the only workflow that affects the
build.

.github/workflows/main.yml

@@ -41,14 +41,14 @@ jobs:
         with:
           filters: |
             needs_build:
-              - '.github/workflows/**'
+              - '.github/workflows/main.yml'
               - 'packages/**'
               - 'test/**'
               - 'pnpm-lock.yaml'
               - 'package.json'
               - 'templates/**'
             needs_tests:
-              - '.github/workflows/**'
+              - '.github/workflows/main.yml'
               - 'packages/**'
               - 'test/**'
               - 'pnpm-lock.yaml'