ci: fix broken github2gerrit-action SHA

The github2gerrit-action SHA ad00dcd (v0.0.16) no longer exists
after the repo was transferred to lfreleng-actions org. Update to
the correct commit SHA for v1.0.8.

Change-Id: I485fa652e7145aaf9660ac89e5533509e3390f79
Signed-off-by: Anil Belur <askb23@gmail.com>
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>

Author: askb

.github/workflows/call-github2gerrit.yaml

@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: Convert GitHub PR to Gerrit Change
-        uses: lfreleng-actions/github2gerrit-action@ad00dcd39ae9aed3260f39b27e7c07b0d88c54ca # v0.0.16
+        uses: lfreleng-actions/github2gerrit-action@de8477030c26a8020e9c95cd6312d5647392b347 # v1.0.8
         with:
           GERRIT_SSH_PRIVKEY_G2G: ${{ secrets.GERRIT_SSH_PRIVKEY_G2G }}
           GERRIT_KNOWN_HOSTS: ${{ vars.GERRIT_KNOWN_HOSTS }}