39d526bde4 test: Bump linter versions (Duncan Dean)
Pull request description:
As per #19346, `mypy==0.700` was incompatible with Python 3.8.
I've bumped the versions of all the linters to their latest stable versions.
Checked with both Python 3.7 and 3.8 and everything still seems to work fine.
ACKs for top commit:
hebasto:
ACK 39d526bde4, I have reviewed the code and it looks OK, I agree it can be merged.
Tree-SHA512: f3ee7fda8095aa25aa68685e863076d52a6b82649770d24b0064d652763c0ceb8ebcbf9024fc74fca45c754e67b2a831dd070b3af23bc099140e6d27e89a5319