Configure checkout action to avoid shallow clone

Added fetch-depth option to checkout action.

Author: SteveSyfuhs

.github/workflows/dotnet.yml

@@ -16,6 +16,9 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+      with:
+          fetch-depth: 0 # avoid shallow clone so nbgv can do its work.
+          
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with: