mkdocs-requirements: Update to Jinja 3.1.6

A security vulnerability was found in Jinja 3.1.5 .  The software is
not impacted by this vulnerability, but there is no harm in updating
to the fixed version.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

docs/_klipper3d/mkdocs-requirements.txt

@@ -1,5 +1,5 @@
 # Python virtualenv module requirements for mkdocs
-jinja2==3.1.5
+jinja2==3.1.6
 mkdocs==1.2.4
 mkdocs-material==8.1.3
 mkdocs-simple-hooks==0.1.3