yet another attempt at fixing github action. Added some comments too.

.github/workflows/firebase-hosting-merge.yml

@@ -11,11 +11,12 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - uses: actions/checkout@v2
-            - run: cd source && yarn install && yarn build
+            - run: cd source # move into source directory
+            - run: yarn install && yarn build # install dependencies and build site
             - uses: FirebaseExtended/action-hosting-deploy@v0
               with:
                   repoToken: "${{ secrets.GITHUB_TOKEN }}"
                   firebaseServiceAccount: "${{ secrets.FIREBASE_SERVICE_ACCOUNT_DEVELOPOMP_SITE }}"
                   channelId: live
-                  projectId: developomp-site
+                  projectId: developomp-site-dev
                   target: dev