Bump mr-smithers-excellent/docker-build-push from 5 to 6

Bumps [mr-smithers-excellent/docker-build-push](https://github.com/mr-smithers-excellent/docker-build-push) from 5 to 6.
- [Release notes](https://github.com/mr-smithers-excellent/docker-build-push/releases)
- [Commits](mr-smithers-excellent/docker-build-push@v5...v6)

---
updated-dependencies:
- dependency-name: mr-smithers-excellent/docker-build-push
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -26,7 +26,7 @@ jobs:
       - uses: actions/checkout@v2
         name: Check out code
 
-      - uses: mr-smithers-excellent/docker-build-push@v5
+      - uses: mr-smithers-excellent/docker-build-push@v6
         name: Build & push Client Docker image
         with:
           image: arifibnshabbir/project-management
@@ -49,7 +49,7 @@ jobs:
       - uses: actions/checkout@v2
         name: Check out code
 
-      - uses: mr-smithers-excellent/docker-build-push@v5
+      - uses: mr-smithers-excellent/docker-build-push@v6
         name: Build & push Server Docker image
         with:
           image: arifibnshabbir/project-management