auth_oidc: drop now-redundant django-jsonfield dependency

setup.py

@@ -132,7 +132,6 @@ setup(name="authentic2",
           'pycryptodome',
           'django-mellon',
           'ldaptools',
-          'django-jsonfield<1.3',
           'jwcrypto>=0.3.1,<1',
           'cryptography',
           'XStatic-jQuery<2',

src/authentic2_auth_oidc/migrations/0001_initial.py

@@ -2,9 +2,9 @@
 from __future__ import unicode_literals
 
 from django.db import migrations, models
-import jsonfield.fields
 import authentic2.a2_rbac.utils
 import authentic2_auth_oidc.models
+import django.contrib.postgres.fields.jsonb
 from django.conf import settings
 import uuid
 
@@ -52,7 +52,7 @@ class Migration(migrations.Migration):
                 ('userinfo_endpoint', models.URLField(max_length=128, verbose_name='userinfo endpoint')),
                 ('end_session_endpoint', models.URLField(max_length=128, null=True, verbose_name='end session endpoint', blank=True)),
                 ('scopes', models.CharField(max_length=128, verbose_name='scopes', blank=True)),
-                ('jwkset_json', jsonfield.fields.JSONField(blank=True, null=True, verbose_name='JSON WebKey set', validators=[authentic2_auth_oidc.models.validate_jwkset])),
+                ('jwkset_json', django.contrib.postgres.fields.jsonb.JSONField(blank=True, null=True, verbose_name='JSON WebKey set', validators=[authentic2_auth_oidc.models.validate_jwkset])),
                 ('idtoken_algo', models.PositiveIntegerField(default=1, verbose_name='IDToken signature algorithm', choices=[(0, 'none'), (1, 'RSA'), (2, 'HMAC')])),
                 ('strategy', models.CharField(max_length=32, verbose_name='strategy', choices=[(b'create', 'create'), (b'none', 'none')])),
                 ('max_auth_age', models.PositiveIntegerField(null=True, verbose_name='max authentication age', blank=True)),

src/authentic2_auth_oidc/models.py

@@ -23,7 +23,7 @@ from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
 from django.core.exceptions import ValidationError
 
-from jsonfield import JSONField
+from django.contrib.postgres.fields import JSONField
 
 from jwcrypto.jwk import JWKSet, InvalidJWKValue, JWK