Inform build environment of setuptools requirement

[Stealthii]

setuptools v58 removed use_2to3 which is required to build this project for Python 3.x setups. In order for this package to be installable by modern package build setups, we need to inform the handler that this version is required.

A pyproject.toml has also been added, to inform PEP 518 builders about our setuptools version requirement.

See pypa/setuptools#2086
Fixes #13

[Stealthii]

Test using Python 3.9 as base python and uv as resolver & builder:

❯ uv init -p 3.9 fudge-pr14
Initialized project `fudge-pr14` at `/Users/stealthii/scratch/fudge-pr14`
❯ cd fudge-pr14
❯ uv add git+https://github.com/Stealthii/fudge --branch bugfix/setuptools-support
 Updated https://github.com/Stealthii/fudge (63ef1ef)
Resolved 2 packages in 736ms
   Built fudge @ git+https://github.com/Stealthii/fudge@63ef1efdddbc1296637285adb8e978b330d490c0
Prepared 1 package in 3.72s
Installed 1 package in 7ms
 + fudge==1.1.1 (from git+https://github.com/Stealthii/fudge@63ef1efdddbc1296637285adb8e978b330d490c0)

[Stealthii]

@RussNelson for review. This would likely suffice for a v1.1.2 that simply includes proper metadata in the source tarballs so that PEP 518 builders can install the package without issues, pending review of #12 which would require a v1.2.x.