Bump html5lib from 0.999 to 0.999999999

Bumps [html5lib](https://github.com/html5lib/html5lib-python) from 0.999 to 0.999999999.
- [Release notes](https://github.com/html5lib/html5lib-python/releases)
- [Changelog](https://github.com/html5lib/html5lib-python/blob/master/CHANGES.rst)
- [Commits](html5lib/html5lib-python@0.999...0.999999999)

---
updated-dependencies:
- dependency-name: html5lib
  dependency-type: direct:production
...

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

requirements.txt

@@ -131,7 +131,7 @@ django-celery==3.1.16
 django-qmethod==0.0.3
 django-subdomain-instances==3.0.2
 django-tastypie==0.12.1
-html5lib==0.999
+html5lib==0.999999999
 kombu==3.0.24
 mechanize==0.2.5
 mimeparse==0.1.3