pyproject.toml: Fix project.license

ValueError: invalid pyproject.toml config: `project.license`.
configuration error: `project.license` must be valid exactly by one definition (2 matches found):

    - keys:
        'file': {type: string}
      required: ['file']
    - keys:
        'text': {type: string}
      required: ['text']
---

See also: https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license

Author: tony

pyproject.toml

@@ -89,7 +89,7 @@ build-backend = "setuptools.build_meta"
 name = "libvcs"
 version = "0.30.1"
 description = "Lite, typed, python utilities for Git, SVN, Mercurial, etc."
-license = "MIT"
+license = {text = "MIT License"}
 authors = ["Tony Narlock <[email protected]>"]
 keywords = [
   "libvcs",