Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/release-on-tag.yaml

@@ -28,7 +28,7 @@ jobs:
       binary_name: md-table-action${{ matrix.file_extension }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: Swatinem/rust-cache@v2