Bump webfactory/ssh-agent from 0.8.0 to 0.9.0

Bumps [webfactory/ssh-agent](https://github.com/webfactory/ssh-agent) from 0.8.0 to 0.9.0.
- [Release notes](https://github.com/webfactory/ssh-agent/releases)
- [Changelog](https://github.com/webfactory/ssh-agent/blob/master/CHANGELOG.md)
- [Commits](webfactory/ssh-agent@v0.8.0...v0.9.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/release.yml

@@ -162,7 +162,7 @@ jobs:
           token: ${{ secrets.DOCS_PAT }}
           path: './docs'
       - name: Setup bot SSH signing key
-        uses: webfactory/ssh-agent@v0.8.0
+        uses: webfactory/ssh-agent@v0.9.0
         env:
           HAS_SSH_PRIVATE_KEY: ${{ secrets.STEP_TRAVIS_CI_GH_PRIVATE_SIGNING_KEY != '' }}
         if: ${{ env.HAS_SSH_PRIVATE_KEY == 'true' }}