Bump bleach from 1.4.3 to 3.1.4

Bumps [bleach](https://github.com/mozilla/bleach) from 1.4.3 to 3.1.4.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v1.4.3...v3.1.4)

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

Author: dependabot[bot]

requirements.txt

@@ -2,7 +2,7 @@ ansicolors==1.1.8
 asn1crypto==0.24.0
 attrs==17.4.0
 bcrypt==3.1.4
-bleach==1.4.3
+bleach==3.1.4
 certifi==2017.11.5
 cffi==1.14.4
 chardet==3.0.4