Audit sanitize gem for Ruby 3.1/3.2

As part of the gem audit we want to assess Ruby 3.1/3.2 compatibility for the following gem(s):

• sanitize

Once complete, please update the audit spreadsheet

Timeline: As of now we are targeting end of Q3 (end of October) to complete this audit and any related issues that require action.

All Ruby 3.1 related issues can be found here: https://gitlab.com/gitlab-org/gitlab/-/issues?label_name[]=Ruby3_1