Bump bleach from 1.4.2 to 3.1.4

Bumps [bleach](https://github.com/mozilla/bleach) from 1.4.2 to 3.1.4.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v1.4.2...v3.1.4)

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

requirements.txt

@@ -1,6 +1,6 @@
 terminaltables==2.1.0
 beautifulsoup4==4.4.1
-bleach==1.4.2
+bleach==3.1.4
 requests==2.20.1
 html5lib==0.999999
 Pmw==2.0.1