build: updating to cache@v4 for github actions because we're past the…

… deprecation date

.github/workflows/repo-checks.yml

@@ -49,7 +49,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/setup-repo
       - name: Cache Emulators
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: /home/runner/.cache/firebase/emulators
           key: ${{ runner.os }}-firebase-emulators-${{ hashFiles('~/.cache/firebase/emulators/**') }}