Use public appveyor image with dotnet 5.0#67

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masterskarpdev/dotnet-version-cli:masterfrom

63-upgrade-to-official-dotnet-5-0-appveyor-image-when-availableskarpdev/dotnet-version-cli:63-upgrade-to-official-dotnet-5-0-appveyor-image-when-availableCopy head branch name to clipboard