[3.8] bpo-47138: Fix documentation build by pinning Jinja version to 3.0.3 (GH-32109)

Co-authored-by: Ned Deily <nad@python.org>

Doc/requirements.txt

@@ -8,6 +8,8 @@ sphinx==2.4.4
 # version 2.4.4. It can be removed after bumping Sphinx version to at
 # least 3.5.4.
 docutils==0.17.1
+# Jinja version is pinned to a version compatible with Sphinx version 2.4.4.
+jinja2==3.0.3
 
 blurb
 

Misc/NEWS.d/next/Documentation/2022-03-28-12-36-17.bpo-47138.TbLXgV.rst

+Pin Jinja to a version compatible with Sphinx version 2.4.4.