Update webfactory/ssh-agent action to v0.9.1

Author: renovate[bot]

.github/workflows/ci.yml

@@ -120,7 +120,7 @@ jobs:
       - run: npx bower install
         working-directory: ./ember
 
-      - uses: webfactory/ssh-agent@v0.5.2
+      - uses: webfactory/ssh-agent@v0.9.1
         with:
           ssh-private-key: ${{ secrets.SSH_PRIVATE_KEY }}