PR #347 Bump lxml from 4.3.2 to 4.6.3 in /docker/scripts

Bumps [lxml](https://github.com/lxml/lxml) from 4.3.2 to 4.6.3.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.3.2...lxml-4.6.3)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docker/scripts/requirements.txt

@@ -2,5 +2,5 @@ Paver==1.3.4
 psycopg2==2.7.5
 eventlet==0.24.1
 gunicorn==19.9.0
-lxml==4.3.2
+lxml==4.6.3
 Werkzeug==0.16.1