Don't strip local version suffix from tag when specified

[mjsir911]

Hi,

We're tracking an internal version forked/downstream from a public project using setuptools_scm and would like to integrate a local version identifier into the generated wheels.

This is currently being done with SETUPTOOLS_SCM_PRETEND_VERSION=0.23+tp.0 but it would be nice for setuptools to not strip the + suffix from the current commit's tag.