Update GH Actions to v6 (#702)

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

Author: renovate[bot]

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download source
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           persist-credentials: false
           fetch-depth: 0

lib/molinillo/.github/workflows/crystal.yml

@@ -18,7 +18,7 @@ jobs:
           crystal: ${{ matrix.crystal }}
 
       - name: Download source
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
 
       - name: Install dependencies
         run: shards install