Update webfactory/ssh-agent action to v0.9.0

Author: renovate[bot]

.github/workflows/publish.yml

@@ -21,7 +21,7 @@ jobs:
         run: make build
 
       - name: Set up SSH agent
-        uses: webfactory/ssh-agent@836c84ec59a0e7bc0eabc79988384eb567561ee2 #v0.7.0
+        uses: webfactory/ssh-agent@dc588b651fe13675774614f8e6a936a468676387 # v0.9.0
         with:
           ssh-private-key: ${{ secrets.AUR_PRIVATE_KEY }}