Bump reportlab from 3.5.34 to 3.5.55 in /apiserver

Bumps [reportlab](http://www.reportlab.com/) from 3.5.34 to 3.5.55.

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

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

apiserver/requirements.txt

@@ -33,7 +33,7 @@ python-memcached==1.59
 python3-openid==3.1.0
 pytz==2019.3
 recommonmark==0.7.1
-reportlab==3.5.34
+reportlab==3.5.55
 requests==2.22.0
 requests-oauthlib==1.3.0
 six==1.13.0