Add Git commit count to version

Directory.Build.targets

<Project>
    <PropertyGroup>
        <GenerateNuspecDependsOn>AddGitCommitCountToVersion;$(GenerateNuspecDependsOn)</GenerateNuspecDependsOn>
        <!-- this is only used in NuGet 4.6.0 -->
        <GetPackageVersionDependsOn>AddGitCommitCountToVersion;$(GetPackageVersionDependsOn)</GetPackageVersionDependsOn>
    </PropertyGroup>
    <Target Name="AddGitCommitCountToVersion" 
            BeforeTargets="PrepareForBuild;_GenerateRestoreProjectSpec" 
            Condition=" '$(DisableGitVersionSuffix)' != 'true' ">

        <Exec Command="git rev-list --count HEAD" ConsoleToMSBuild="true" StandardOutputImportance="low">
            <Output TaskParameter="ConsoleOutput" PropertyName="GitCommitCount" />
        </Exec>

        <PropertyGroup>
            <PreReleaseLabel Condition=" '$(PreReleaseLabel)' == '' ">beta</PreReleaseLabel>
            <VersionCommitCountSuffix>$(GitCommitCount.PadLeft(6, '0'))</VersionCommitCountSuffix>
            <Version>$(Version)-$(PreReleaseLabel)-$(VersionCommitCountSuffix)</Version>
            <PackageVersion>$(Version)</PackageVersion>
        </PropertyGroup>
    </Target>
</Project>