chore(deps): update actions/checkout action to v6

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
@@ -38,7 +38,7 @@ jobs:
           - rvm: 2.7
             puppet_gem_version: "~> 7.0"
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
@@ -74,7 +74,7 @@ jobs:
           - ubuntu-20-04-puppet6
           - ubuntu-20-04-puppet7
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with: