Merge pull request #647 from H-uru/checkout-v2

Update to checkout v2

.github/workflows/linux-ci.yml

@@ -5,7 +5,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Install dependencies
       run: |
         sudo apt update