Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

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

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

Author: dependabot[bot]

.github/workflows/baseruby.yml

@@ -34,7 +34,7 @@ jobs:
           - ruby-3.1
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/cache@v4
         with:
           path: .downloaded-cache

.github/workflows/bundled_gems.yml

@@ -28,7 +28,7 @@ jobs:
           echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
           echo "TODAY=$(date +%F)" >> $GITHUB_ENV
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/cache@v4
         with:

.github/workflows/check_dependencies.yml

@@ -39,7 +39,7 @@ jobs:
         run: |
           git config --global advice.detachedHead 0
           git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/cache@v4
         with:
           path: .downloaded-cache

.github/workflows/check_misc.yml

@@ -9,7 +9,7 @@ jobs:
   checks:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Check if C-sources are US-ASCII
         run: |
           ! grep -r -n '[^	 -~]' *.[chy] include internal win32/*.[ch]

.github/workflows/codeql-analysis.yml

@@ -36,7 +36,7 @@ jobs:
         sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
 
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - uses: actions/cache@v4
       with:

.github/workflows/compilers.yml

@@ -224,7 +224,7 @@ jobs:
       - name: setenv
         run: |
           echo "GNUMAKEFLAGS=-sj$((1 + $(nproc --all)))" >> $GITHUB_ENV
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           path: src
       - uses: actions/cache@v4

.github/workflows/macos.yml

@@ -35,7 +35,7 @@ jobs:
         run: |
           git config --global advice.detachedHead 0
           git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           path: src
       - uses: actions/cache@v4

.github/workflows/mingw.yml

@@ -54,7 +54,7 @@ jobs:
           git config --global core.eol lf
           git config --global advice.detachedHead 0
           git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           path: src
       - uses: actions/cache@v4

.github/workflows/mjit.yml

@@ -40,7 +40,7 @@ jobs:
         run: |
           git config --global advice.detachedHead 0
           git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           path: src
       - uses: actions/cache@v4

.github/workflows/spec_guards.yml

@@ -30,7 +30,7 @@ jobs:
           - ruby-3.1
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}