ci: ensure that generated files have been regenerated as part of prer…

…elease checks (#1312)

This adds a job to the prerelease checks workflow to make sure that
generated code is up-to-date at time of release - currently the only
code we actually generate is the static list of `spdx` licenses which
are sourced from
https://raw.githubusercontent.com/spdx/license-list-data/main/json/licenses.json

To verify this job works and showcase it's output, I've included a
commit adding it to the pr checks workflow - when we're happy with this,
I'll drop that commit before taking this out of draft

Also, here's an image of the annotation both on the file and in the
action log:


![image](https://github.com/user-attachments/assets/36a168d6-3f60-4efc-835e-842892d2530b)

![image](https://github.com/user-attachments/assets/d1b30f7f-19cd-4f98-8324-61b24abd0f8f)

Co-authored-by: Xueqin Cui <[email protected]>

.github/workflows/prerelease-check.yml

@@ -105,6 +105,28 @@ jobs:
         uses: ./.github/workflows/test-action
         with:
           codecov_token: ${{ secrets.CODECOV_TOKEN }}
+  generators:
+    permissions:
+      contents: read # to fetch code (actions/checkout)
+    name: (re)generate code
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
+        with:
+          persist-credentials: false
+          ref: ${{ inputs.commit }}
+      - name: Set up Go
+        uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+        with:
+          go-version: stable
+          check-latest: true
+      - name: Run generators
+        run: go generate ./...
+      - run: |
+          git diff --name-only \
+            | xargs -I '{}' bash -c \
+              'echo "::error file={}::This needs to be regenerated by running \`go generate ./...\`" && false'
   release-helper:
     permissions:
       contents: read # to fetch code (actions/checkout)