chore(deps): update actions/checkout digest to b4ffde6 (#303)

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

Author: renovate[bot]

.github/workflows/pull_request.yml

@@ -11,7 +11,7 @@ jobs:
         ruby: [ '2.7', '3.0', '3.1' ]
     name: Ruby v${{ matrix.ruby }}
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}