Use latest version of actions/checkout in Go release workflow

Previously, a significantly outdated version of the actions/checkout GitHub Actions workflow was in use.

Author: per1234

workflow-templates/dependabot/workflow-template-copies/.github/workflows/release-go-task.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
         with:
           fetch-depth: 0
 

workflow-templates/release-go-task.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
         with:
           fetch-depth: 0