fix: pin pydyf until weasyprint adjusts for its deprecations (#7945)

requirements.txt

@@ -49,6 +49,7 @@ oic>=1.3    # Used only by tests
 Pillow>=9.1.0
 psycopg2>=2.9.6
 pyang>=2.5.3
+pydyf>0.8.0,<0.10.0 # until weasyprint adjusts for 0.10.0 and later
 pyflakes>=2.4.0
 pyopenssl>=22.0.0    # Used by urllib3.contrib, which is used by PyQuery but not marked as a dependency
 pyquery>=1.4.3