feat(docker): add lxml as a requirement

Add lxml as a requirement for a deduplication script we'll use to reduce
deployment size on GitHub.

Signed-off-by: Randolph Sapp <rs@ti.com>

Author: StaticRocket

requirements.txt

@@ -8,6 +8,7 @@ docutils==0.21.2
 idna==3.10
 imagesize==1.4.1
 Jinja2==3.1.5
+lxml==6.0.0
 markdown-it-py==3.0.0
 MarkupSafe==3.0.2
 mdurl==0.1.2