Nuget pack doesn't support blank <version> in .nuspec even though version is passed on the command line

[samrueby]

Details about Problem

When running nuget pack with a .nuspec file that contains an empty version and passing -Version on the command line, nuget will fail with the error:

An error occured while trying to parse the value '' of property 'version' in the manifest file.
Value cannot be null or an empty string.
Parameter name: value

However, you put in a bogus version identifier in the nuspec file, the same command will run happily, with the version number passed on the command line.

NuGet product used: NuGet.exe

NuGet version (x.x.x.xxx): 4.9.3.5777

OS version (i.e. win10 v1607 (14393.321)): Win 10 1903

Detailed repro steps

1. Create a valid .nuspec file, but with an empty version, i.e. <version></version>

2. Run nuget.exe pack the.nuspec -Version 1.2.3.4

3. See error.

4. Replace version in .nuspec file with <version>0.0.0.0</version>

5. Run same command as above

6. See success.