Use setuptools-scm for versioning

[duncanmmacleod]

This PR updates the project metadata to use setuptools-scm for version handling. I have also completely removed the setup.py script as the project is fully described in the setup.cfg file. This means that a PEP-517 builder (e.g. pip) is needed to build the project (you can't execute python setup.py ...).

[codecov]

Codecov Report

Merging #36 (af3325d) into main (72f206c) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main       #36   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         6           
  Lines           93        96    +3     
=========================================
+ Hits            93        96    +3     

Flag	Coverage Δ
Linux	100.00% <100.00%> (ø)
Windows	100.00% <ø> (ø)
macOS	100.00% <100.00%> (ø)
python3.10	100.00% <100.00%> (ø)
python3.6	100.00% <100.00%> (ø)
python3.7	100.00% <100.00%> (ø)
python3.8	100.00% <100.00%> (ø)
python3.9	100.00% <100.00%> (ø)

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Impacted Files	Coverage Δ
dqsegdb2/__init__.py	100.00% <100.00%> (ø)

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