ci: add job to ensure that ecosystem lists are all in sync

Signed-off-by: Gareth Jones <jones258@gmail.com>

.github/workflows/checks.yml

@@ -57,3 +57,22 @@ jobs:
           check-latest: true
 
       - run: go test ./...
+
+  ecosystem_lists:
+    permissions:
+      contents: read # to fetch code (actions/checkout)
+    name: Check ecosystem lists
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@f677139bbe7f9c59b41e40162b753c062f5d49a3 # v5.2.0
+        with:
+          python-version: 3.13
+      - run: python3 ./scripts/update-ecosystems-lists.py
+      - run: |
+          git diff --name-only \
+            | xargs -I '{}' bash -c \
+              'echo "::error file={}::This needs to be regenerated by running \`python3 ./scripts/update-ecosystems-lists.py\`" && false'