Do not explicitly specify the .NET SDK version in actions/setup-dotnet

The version from the global.json file will be used, see https://github.com/actions/setup-dotnet/blob/499789684c9a0d41c9b3f0d66a785ba17b1d51ab/src/setup-dotnet.ts#L12

Author: 0xced

.github/workflows/continuous-integration.yml

@@ -23,10 +23,8 @@ jobs:
       nupkg-filename: ${{ steps.dotnet-pack.outputs.nupkg-filename }}
       release-body: ${{ steps.tag-message.outputs.release-notes }}
     steps:
-      - name: Install .NET 6.0 SDK
+      - name: Install .NET SDK
         uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: 6.0.x
       - name: Checkout git repository
         uses: actions/checkout@v2
         with: