Update email domain etc in pyproject.toml

[phillxnet]

We currently make use of dated support email domain in pyproject.toml, as well as a failure to include the co-maintainer @FroggyFlox.

[phillxnet]

Another element to address under this issue, re pyproject.toml would be the following classifier:

"Development Status :: 4 - Beta",

We are currently in testing but at the final Release Candidate phase; pushing for our next stable rpm stage. So this should likely be changed to:

"Development Status :: 5 - Production/Stable",

N.B. the 5 is a external designation, coincidentally the same as our current testing release major number:

see: https://pypi.org/classifiers/

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References:

• Technical: https://packaging.python.org/en/latest/specifications/pyproject-toml/#pyproject-toml-spec
• Overview: https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#writing-pyproject-toml