Release notes for v1.0.0-M21

Update the date

Merge pull request http4s#4720 from http4s/tomcat-9.0.45

Update tomcat-catalina, tomcat-coyote, ... to 9.0.45

Merge pull request http4s#4664 from CremboC/cats-effect-3.0

Upgrade to cats-effect 3.0.0 final and fs2 3.0.0 final

Fix header level in changelog

Merge pull request http4s#4656 from http4s/jetty-9.4.34

Upgrade to jetty-9.4.39

Merge branch 'series/0.22' into main

Merge pull request http4s#4579 from http4s/regenerate-mimedb

Regenerate MimeDb

Merge branch '0.22.0-M4' into 1.0.0-M17

Merge branch 'series/0.22' into main