Update loohaf to 2.2.1

[AlinaMoskieva]

Summary

Update loofah to 2.2.1 to eliminate CVE-2018-8048

Test plan

Run bin/quality and make sure that no vulnerabilities are found

Review notes

While reviewing pull-request (especially when it's your pull-request),
please make sure that:

• you understand what problem is solved by PR and how is it solved
• new tests are in place, no redundant tests
• DB schema changes reflect new migrations
• newly introduces DB fields have indexes and constraints
• routes are RESTful, no useless routes
• there are no missed files (migrations, view templates)
• required ENV variables added and described in .env.example and added to Heroku
• associated Heroku review app works correctly with introduced changes

Deploy notes

–