tests: Run check-runners as part of the tests

.github/workflows/tests.yml

@@ -182,7 +182,7 @@ jobs:
             exit "0"
           fi
 
-  snapshots:
+  check-snapshots:
     name: "🔍 Check for valid snapshot urls"
     runs-on: ubuntu-20.04
     steps:
@@ -193,6 +193,17 @@ jobs:
       - name: Check for valid snapshot urls
         run: ./tools/check-snapshots --errors-only .
 
+  check-runners:
+    name: "🔍 Check for missing or unused runner repos"
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+      - name: Check for missing or unused runner repos
+        run: ./tools/check-runners
+
   shellcheck:
     name: "🐚 Shellcheck"
     runs-on: ubuntu-20.04