[ci] Temporarily added jsonfield

- Was removed upstream
- Will be removed, but we need it for CI builds in the short term

Author: nemesifier

requirements.txt

@@ -16,3 +16,4 @@ django-cache-memoize~=0.2.1
 shortuuid~=1.0.13
 netaddr~=1.3.0
 django-import-export~=4.3.14
+jsonfield>=3.1.0,<4.0.0