Bump bleach from 3.1.0 to 3.1.4

Bumps [bleach](https://github.com/mozilla/bleach) from 3.1.0 to 3.1.4.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v3.1.0...v3.1.4)

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

requirements.txt

@@ -5,7 +5,7 @@ atomicwrites==1.2.1
 attrs==18.1.0
 Babel==2.6.0
 black==19.10b0
-bleach==3.1.0
+bleach==3.1.4
 certifi==2018.8.24
 chardet==3.0.4
 click==6.7