Bump Nerdbank.GitVersioning from 3.1.71 to 3.1.74 in /Rx.NET/Source
Bumps [Nerdbank.GitVersioning](https://github.com/dotnet/Nerdbank.GitVersioning) from 3.1.71 to 3.1.74.
- [Release notes](https://github.com/dotnet/Nerdbank.GitVersioning/releases)
- [Commits](https://github.com/dotnet/Nerdbank.GitVersioning/compare/v3.1.71...v3.1.74)
Signed-off-by: dependabot-preview[bot] <[email protected]>