fix build - removes v from release name

.github/workflows/dotnetcore.yml

@@ -35,7 +35,7 @@ jobs:
         run: dotnet test src/PostalCodes.UnitTests/PostalCodes.UnitTests.csproj
       - name: Extract Version from Release Tag
         id: get_version
-        run: echo "VERSION=$(echo '${{ github.event.release.tag_name || env.DEFAULT_VERSION }}' | sed -e 's/^v\.//')" >> $GITHUB_ENV
+        run: echo "VERSION=$(echo '${{ github.event.release.tag_name || env.DEFAULT_VERSION }}' | sed -e 's/^v//')" >> $GITHUB_ENV
       - name: Create nuget package
         run: dotnet pack . -p:PackageVersion=${{ env.VERSION }} -o out --no-build
       - name: Install dotnet-validate