Consistently use checkout@v2

.github/workflows/go.yml

@@ -15,7 +15,7 @@ jobs:
           go-version: 1.13
 
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
 
       - name: Verify dependencies
         run: go mod verify

.github/workflows/releases.yml

@@ -80,7 +80,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
       - name: Copy release
         id: copy
         uses: ./.github/actions/copy-release-to-another-repo