Bump bleach from 2.1.3 to 3.1.4 (#25)

Bumps [bleach](https://github.com/mozilla/bleach) from 2.1.3 to 3.1.4.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v2.1.3...v3.1.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -3,7 +3,7 @@ astor==0.7.1
 atomicwrites==1.2.1
 attrs==18.2.0
 backcall==0.1.0
-bleach==2.1.3
+bleach==3.1.4
 certifi==2018.10.15
 chardet==3.0.4
 cycler==0.10.0