Release workflow: update checkout action to v2

Author: NReilingh

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
     - name: Package
       run: tar -cvzf archive-fusionvm.tar.gz archive_fusionvm
     - name: Upload Asset to Release