Bump bleach from 2.1.2 to 3.3.0

Bumps [bleach](https://github.com/mozilla/bleach) from 2.1.2 to 3.3.0.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v2.1.2...v3.3.0)

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

Author: dependabot[bot]

requirements.txt

@@ -1,7 +1,7 @@
 --no-binary :all:
 
 libsass==0.18.0
-bleach==2.1.2
+bleach==3.3.0
 certifi==2018.1.18
 chardet==3.0.4
 confusable-homoglyphs==3.0.0