Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/main.yml

@@ -6,7 +6,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v6
     - name: Mirror + trigger CI
       uses: sandykadam/gitlab-mirror-and-ci-action@master
       with:

.github/workflows/nodejs.yml

@@ -12,7 +12,7 @@ jobs:
         node-version: [18.x]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v6
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v2
       with: