Bump actions/checkout from 4 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/publish_gem_rubygems_org.yml

@@ -12,7 +12,7 @@ jobs:
       packages: write
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v7
 
     # Set up the latest version of Ruby
     - name: Set up Ruby

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
     steps:
     # Step 1: Check out the repository
     - name: Check out repository code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v7
 
     # Step 2: Set up Ruby
     - name: Set up Ruby