chore(deps): update actions/checkout action to v6 (#28)

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

Author: renovate[bot]

.github/workflows/nightly.yml

@@ -28,7 +28,7 @@ jobs:
       CCACHE_SLOPPINESS: time_macros
       SCCACHE_GHA_ENABLED: "true"
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up ccache for ${{ matrix.arch }}
       uses: actions/[email protected]

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
       CCACHE_SLOPPINESS: time_macros
       SCCACHE_GHA_ENABLED: "true"
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up ccache for ${{ matrix.arch }}
       uses: actions/[email protected]