We need to update nokogiri to 1.11.0 due to CVE-2020-26247.
How to test: confirm that posting and importing works with formatting work fine.
Posting a new work with formatting works fine.
Importing https://ao3testing.dreamwidth.org/3508.html works fine.
Gave posting a work with the RTE test document (which has a lot of formatting) a whirl; it looked fine.
Tried importing https://ao3testing.dreamwidth.org/1253.html; also looked good.