Update deps, allow Python 3.9, drop Fedora 32 (#5121)

* Update deps + allow Python 3.9

* Add in updates from Jack's branch

* Fix multiple target for cross-reference warnings

* Update a few more Python 3.8 occurrences

* Bump further

* Don't install tox in CodeQL environment

* Bump Python version in docs to 3.9.7

* more bumps

* Add missing pin

* Stop using the deprecated distro.linux_distribution()

* Suppress deprecation warning

* Fix OpenSUSE Leap instructions

* Drop Fedora 32

* Add Python 3.10-dev to CI

* meh

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

tox.ini

@@ -6,6 +6,7 @@
 [tox]
 envlist =
     py38
+    py39
     docs
     style
 skip_missing_interpreters = True
@@ -16,6 +17,8 @@ whitelist_externals =
     pytest
     pylint
 extras = voice, test
+setenv =
+    TOX_RED = 1
 commands =
     python -m compileall ./redbot/cogs
     pytest
@@ -27,6 +30,7 @@ whitelist_externals =
     pytest
 extras = voice, test, postgres
 setenv =
+    TOX_RED = 1
     RED_STORAGE_TYPE=postgres
 passenv =
     # Use the following env vars for connection options, or other default options described here: