Bump webfactory/ssh-agent from 0.7.0 to 0.9.1 (#330)

Bumps [webfactory/ssh-agent](https://github.com/webfactory/ssh-agent) from 0.7.0 to 0.9.1.
- [Release notes](https://github.com/webfactory/ssh-agent/releases)
- [Changelog](https://github.com/webfactory/ssh-agent/blob/master/CHANGELOG.md)
- [Commits](webfactory/ssh-agent@v0.7.0...v0.9.1)

---
updated-dependencies:
- dependency-name: webfactory/ssh-agent
  dependency-version: 0.9.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/test-behat.yml

@@ -75,7 +75,7 @@ jobs:
         run: echo "GIT_SSH_COMMAND=ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" >> $GITHUB_ENV
 
       - name: Install SSH key
-        uses: webfactory/ssh-agent@v0.7.0
+        uses: webfactory/ssh-agent@v0.9.1
         with:
           ssh-private-key: ${{ secrets.SITE_OWNER_SSH_PRIVATE_KEY }}