Bump bleach from 3.1.4 to 3.3.0

Bumps [bleach](https://github.com/mozilla/bleach) from 3.1.4 to 3.3.0.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v3.1.4...v3.3.0)

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

Author: dependabot[bot]

requirements.txt

@@ -3,7 +3,7 @@ appnope==0.1.0
 attrs==19.1.0
 backcall==0.1.0
 biopython==1.73
-bleach==3.1.4
+bleach==3.3.0
 bokeh==1.3.1
 certifi==2019.6.16
 chardet==3.0.4