Update actions/checkout digest to b4ffde6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -39,7 +39,7 @@ jobs:
             target: arm64
     name: ${{ matrix.os }} (node=${{ matrix.node }}, host=${{ matrix.host }}, target=${{ matrix.target }})
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
       - uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node }}
@@ -136,7 +136,7 @@ jobs:
             node: 18
     name: ${{ matrix.variant }} (node=${{ matrix.node }}, target=${{ matrix.target }})
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3