Bump bleach from 1.5.0 to 3.1.4 in /benchmarks/scripts

Bumps [bleach](https://github.com/mozilla/bleach) from 1.5.0 to 3.1.4.
- [Release notes](https://github.com/mozilla/bleach/releases)
- [Changelog](https://github.com/mozilla/bleach/blob/master/CHANGES)
- [Commits](mozilla/bleach@v1.5...v3.1.4)

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

benchmarks/scripts/requirements.txt

@@ -5,7 +5,7 @@ astor==0.7.1
 avro==1.8.2
 backports.functools-lru-cache==1.5
 backports.weakref==1.0.post1
-bleach==1.5.0
+bleach==3.1.4
 cachetools==3.1.0
 certifi==2019.3.9
 chardet==3.0.4