Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
         node-version: [12.x]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v4

.github/workflows/voting.yml

@@ -8,6 +8,6 @@ jobs:
   democracy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Evaluate vote
         uses: myyk/git-democracy@v2