build(deps): bump actions/checkout from 4 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build-and-test.yml

@@ -49,7 +49,7 @@ jobs:
 
     steps:
     # Check out repo under sub-dir so other repo can be checked out
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
       with:
         path: gitgitgadget
 
@@ -90,7 +90,7 @@ jobs:
       if: env.GGG_SMTP_USER || env.GGG_SMTP_PASS || env.GGG_SMTP_HOST
 
     # Check out github-glue.test.ts repo if configured for it
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
       with:
         repository: ${{ github.repository_owner }}/${{ env.GGG_REPOSITORY }}
         token: ${{ env.GGG_TOKEN }}