chore(deps): update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/whiskers-check.yml

@@ -11,6 +11,6 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: catppuccin/setup-whiskers@v2
       - run: whiskers dankmaterialshell.tera --check catppuccin.json