Docs updates

[pacrob]

Docs dependencies were pinned too low and bumpversion is deprecated for bump-my-version.

Closes #71

Actions Taken

• Removed upper pins for Sphinx and coverage
• Replaced bumpversion with bump-my-version, moved config from bumpversion.cfg to pyproject.toml.
• Added towncrier dependency + config, added newsfragment folder + newsfragments for recent PRs.
• Remove calling setup.py to build, added build dependency and use that instead.
• Merged test dependencies into dev.
• aiodns dependency was unused, removed it, but required dnspython was not in dependencies, added it.

[pacrob]

@acul - noticed resolver tests would not run. It looks like you were using the dnspython library instead of the aiodns one that was in dependencies. I've replaced it in this PR, but could you clarify what you meant to do?

I've also added towncrier and newsfragments, summarizing from your recent PRs. Please check what I've added to make sure you agree with what I've written. Thanks!

[acul71]

dnspython library instead of the aiodns

Fantastic work @pacrob, thanks
I think I've added manually dnspython and forgot to update dependencies file.
Thanks for fixing that and add all the newsfragments.
Can be merged.
PS: Is in this repo Cl for running tests ? #69

[pacrob]

Is in this repo Cl for running tests ? #69

I think yes, I aim to pick that up soon.