Bump bleach from 3.1.0 to 3.1.2

Bumps [bleach](https://github.com/mozilla/bleach) from 3.1.0 to 3.1.2.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v3.1.0...v3.1.2)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -9,7 +9,7 @@ flask-peewee==3.0.3
 feedparser==5.2.1
 #feedformatter
 tweepy==3.8.0
-bleach==3.1.0
+bleach==3.1.2
 # a lot of our modules are separately pulled in later:
 #importlib
 # for passwords: