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

@@ -4,7 +4,7 @@ astroid==2.2.5
 async-timeout==3.0.1
 atomicwrites==1.3.0
 attrs==19.1.0
-bleach==3.1.0
+bleach==3.1.4
 cachetools==3.1.1
 certifi==2019.6.16
 chardet==3.0.4