Misleading message about exported nupkg file name

[GreyCat]

Describe the bug

When attempting to do vcpkg export with overriding a --nuget-version with something shorter than 3 dot-separated numbers (as per semver standard), vcpkg silently fixes that to match "X.Y.Z" semver schema by adding zeroes, and then shows a very misleading message about a file generated, which uses whatever a user has passed on the command line rather than what vcpkg used in reality while writing a file.

Environment

• OS: Windows
• Compiler: MSVC 2019

To Reproduce
Steps to reproduce the behavior:

1. Run ./vcpkg export gtest --nuget --nuget-id=gtest --nuget-version=1.2
2. vcpkg reports this:

   NuGet package exported at: X:\vcpkg\gtest.1.2.nupkg
   

3. However, in reality, exported file is found in X:\vcpkg\gtest.1.2.0.nupkg, not X:\vcpkg\gtest.1.2.nupkg.

Expected behavior

vcpkg message should report correct file name, matching what it exports.

[PhoebeHui]

@GreyCat, thanks for reporting this issue!