Add workflow to track schema changes

.github/workflows/api-tracker.yaml

@@ -0,0 +1,74 @@
+name: Prefect API tracker
+
+'on':
+  # Run weekly on Monday at 9:00 AM UTC
+  schedule:
+    - cron: '0 9 * * 1'
+
+  # Allow manual triggering
+  workflow_dispatch: {}
+
+  # Allow testing from PRs
+  # TODO: remove before merge
+  pull_request:
+    branches:
+      - main
+
+permissions: {}
+
+jobs:
+  detect-api-drift:
+    permissions:
+      # required to read from the repo
+      contents: read
+      # required for the paths-filter GHA, if workflow triggered by PR
+      pull-requests: read
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # We need history to compare with previous schemas
+
+      - name: Get previous API schema
+        uses: actions/download-artifact@v4
+        with:
+          path: openapi.json
+
+      - name: Compare with latest schema
+        run: |
+          /bin/bash ./scripts/compare.sh
+
+      - name: Check if diff found
+        id: diff
+        uses: andstor/file-existence-action@v3
+        with:
+          files: 'diff.md'
+
+      - name: Create GitHub issue for changes
+        if: steps.diff.outputs.files_exists == 'true'
+        run: |
+          gh issue create \
+            --title='Prefect API change detected' \
+            --body-file='diff.md' \
+            --label='maintenance'
+
+      - name: Prepare current schema for upload
+        run: |
+          # Remove the previous schema file
+          rm openapi.json
+          # Rename the current schema file
+          mv openapi-current.json openapi.json
+
+      - name: Upload current schema for future comparison
+        if: steps.diff.outputs.files_exists == 'true'
+        uses: actions/upload-artifact@v4
+        with:
+          path: openapi.json
+          overwrite: true
+          # The flow will run every 7 days, so no need to
+          # hold on to the file for much longer than that.
+          retention-days: 10
+          # We want to make sure the current schema is uploaded
+          # at the end to generate proper incremental diffs.
+          if-no-files-found: error