Bring back flake8 for python 3.6 (#4394)

Ruff is incompatible with python 3.6. Since we still support 3.6,
bring back the option to run flake8 from the Makefile.

Also bump ruff version to bring flake8 parity.

Fixes GH-4339

tools/run-lint

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+# This file runs flake8 for compatibility's sake. As soon as we move off python 3.6, this should be changed to use ruff.
+
 CR="
 "
 pycheck_dirs=( "cloudinit/" "tests/" "tools/"  "setup.py" )
@@ -11,7 +13,7 @@ else
    files=( "$@" )
 fi
 
-cmd=( "python3" -m "ruff" "${files[@]}" )
+cmd=( "python3" -m "flake8" "${files[@]}" )
 
 echo "Running: " "${cmd[@]}" 1>&2
 exec "${cmd[@]}"

tox.ini

@@ -27,7 +27,7 @@ isort==5.10.1
 mypy==0.950
 pylint==2.13.9
 pytest==7.0.1
-ruff==0.0.282
+ruff==0.0.285
 types-jsonschema==4.4.2
 types-oauthlib==3.1.6
 types-passlib==1.7.7.12