build(deps): Bump actions/checkout from 5 to 6 (#24)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build-and-release-docker-image.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Build the Docker image
       run: docker build . -t z9pascal/pgbouncer-container:$(cat ./Dockerfile | grep -Po 'version="\K.*?(?=")')-latest

.github/workflows/build-docker-image.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Build the Docker image
       run: docker build . --file Dockerfile --tag pgbouncer-container:$(cat ./Dockerfile | grep -Po 'version="\K.*?(?=")')-$(date +%s)