feat: publish supported python versions in --about

[kgpayne]

Closes #1628
Closes #1403

[codecov]

Codecov Report

Merging #1800 (398c905) into main (0d1b918) will decrease coverage by 0.08%.
The diff coverage is 86.95%.

❗ Current head 398c905 differs from pull request most recent head b646de2. Consider uploading reports for the commit b646de2 to get more accurate results

@@            Coverage Diff             @@
##             main    #1800      +/-   ##
==========================================
- Coverage   86.44%   86.37%   -0.08%     
==========================================
  Files          59       59              
  Lines        4974     4992      +18     
  Branches      813      816       +3     
==========================================
+ Hits         4300     4312      +12     
- Misses        476      481       +5     
- Partials      198      199       +1     

Impacted Files	Coverage Δ
singer_sdk/about.py	98.36% <85.71%> (-1.64%)	⬇️
singer_sdk/plugin_base.py	84.06% <87.50%> (+0.13%)	⬆️

... and 1 file with indirect coverage changes

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[kgpayne]

@edgarrmondragon FYI. We talked about this in our ☕️ chat, and you mentioned using a different approach in tap-linkedin? How do you feel about adding an optional package_name attr to facilitate lookups of the package version and other package metadata?

[edgarrmondragon]

LGTM! Just a single nit/suggestion.

[edgarrmondragon]

@kgpayne I pushed a fix for mypy. Feel free to merge!