ci: update cffi

See: #1020

Author: NicolasT

.github/workflows/constraints.txt

@@ -12,7 +12,7 @@ cachecontrol==0.13.1
     # via poetry
 certifi==2023.5.7
     # via requests
-cffi==1.15.1
+cffi==1.16.0
     # via cryptography
 charset-normalizer==3.1.0
     # via requests