Add hermes commit to github action cache (facebook#43067)

Summary:
The test_ios_rntester-Hermes which runs in github actions was created to make sure that recent commits on Hermes/main won't be breaking React Native
However, we discovered that the job was using a cached version of hermes and it was't really downloading the latest hermes every time.

With this change, the cocoapods cache will be invalidated whenever there is a commit on hermes/main, forcing the job to reinstall the dependencies when that happens.

bypass-github-export-checks

## Changelog:
[internal] - Fixed GH Action job to properly refetch newest version on Hermes when it changes.

Pull Request resolved: facebook#43067

Test Plan:
Github Actions must be green and the action should show that a new version of Hermes is downloaded.

The commit is downloaded here:
 {F1457505882}

And it is used here, notice the last hash:
 {F1457505989}

Reviewed By: motiz88

Differential Revision: D53853963

Pulled By: cipolleschi

fbshipit-source-id: 7a65dd72a21b6da12b826273d1c92bb90b678652

.github/workflows/ios-tests.yml

@@ -21,6 +21,13 @@ jobs:
           cache: 'yarn'
       - name: Yarn Install
         run: yarn install
+      - name: Get latest commit from Hermes
+        run: |
+          mkdir -p tmp/hermes
+          HERMES_TAG_SHA=$(git ls-remote https://github.com/facebook/hermes main | cut -f 1 | tr -d '[:space:]')
+          echo $HERMES_TAG_SHA > tmp/hermes/hermesversion
+          echo "Latest Commit is:"
+          cat tmp/hermes/hermesversion
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
@@ -29,7 +36,7 @@ jobs:
         uses: actions/cache@v3
         with:
           path: packages/rn-tester/Pods
-          key: ${{ runner.os }}-RNTesterPods-${{ hashFiles('packages/rn-tester/Podfile.lock') }}-${{ hashFiles('packages/rn-tester/Podfile') }}
+          key: v1-${{ runner.os }}-RNTesterPods-${{ hashFiles('packages/rn-tester/Podfile.lock') }}-${{ hashFiles('packages/rn-tester/Podfile') }}-${{ hashFiles('tmp/hermes/hermesversion') }}
       - name: Pod Install
         run: |
           cd packages/rn-tester