Bump checkout action to latest stable (#43)

Author: dundargoc

.github/workflows/test.yml

@@ -10,21 +10,21 @@ jobs:
   build: # make sure build/ci work properly
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - run: |
           npm install
       - run: |
           npm run all
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - run: npm ci
       - run: npm test
   smoketest: # make sure the action works on a clean machine without building
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ./
         with:
           token: ${{ secrets.GITHUB_TOKEN }}