chore: update linter, drop support for python 3.8 and 3.9

[tserg]

What I did

Drop support for python 3.8 and 3.9.

This is intended to facilitate some breaking changes (not exhaustive):

• Using match syntax
• Switching to eth-stdlib for ABI encoding

How I did it

Update configuration files and CI.

How to verify it

Commit message

chore: drop support for python 3.8 and 3.9

Description for the changelog

Cute Animal Picture

[codecov-commenter]

Codecov Report

Merging #3325 (b8509b1) into master (5b5d9d9) will decrease coverage by 0.10%.
The diff coverage is 63.93%.

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@@            Coverage Diff             @@
##           master    #3325      +/-   ##
==========================================
- Coverage   88.93%   88.83%   -0.10%     
==========================================
  Files          84       84              
  Lines       10606    10606              
  Branches     2216     2215       -1     
==========================================
- Hits         9432     9422      -10     
- Misses        768      778      +10     
  Partials      406      406              

Impacted Files	Coverage Δ
vyper/__main__.py	0.00% <ø> (ø)
vyper/ast/folding.py	93.27% <ø> (ø)
vyper/ast/natspec.py	98.76% <ø> (ø)
vyper/builtins/_signatures.py	97.64% <ø> (ø)
vyper/cli/vyper_compile.py	68.38% <ø> (ø)
vyper/cli/vyper_json.py	78.74% <ø> (-0.35%)	⬇️
vyper/cli/vyper_serve.py	0.00% <ø> (ø)
vyper/codegen/abi_encoder.py	88.88% <ø> (ø)
.../codegen/function_definitions/external_function.py	100.00% <ø> (ø)
vyper/codegen/return_.py	94.73% <ø> (ø)
... and 23 more

... and 1 file with indirect coverage changes

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