Bump simplybusiness/dobby from 3 to 4

Bumps [simplybusiness/dobby](https://github.com/simplybusiness/dobby) from 3 to 4.
- [Release notes](https://github.com/simplybusiness/dobby/releases)
- [Commits](simplybusiness/dobby@v3...v4)

---
updated-dependencies:
- dependency-name: simplybusiness/dobby
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/dobby-actions.yml

@@ -22,7 +22,7 @@ jobs:
         with:
           bundler-cache: true
       - name: Bump version
-        uses: simplybusiness/dobby@v3
+        uses: simplybusiness/dobby@v4
         env:
           DOBBY_APP_ID: ${{ secrets.DOBBY_APP_ID }}
           DOBBY_PRIVATE_KEY: ${{ secrets.DOBBY_PRIVATE_KEY }}