OAuth models: increase avatar_url lenght (#8472)

Ref https://sentry.io/organizations/read-the-docs/issues/2629336384/?environment=production&project=148442&referrer=alert_email

Author: stsewd

readthedocs/oauth/migrations/0015_increase_avatar_url_length.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.2.24 on 2021-09-07 13:30
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('oauth', '0014_remove_remoterepository_project'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='remoteorganization',
+            name='avatar_url',
+            field=models.URLField(blank=True, max_length=255, null=True, verbose_name='Avatar image URL'),
+        ),
+        migrations.AlterField(
+            model_name='remoterepository',
+            name='avatar_url',
+            field=models.URLField(blank=True, max_length=255, null=True, verbose_name='Owner avatar image URL'),
+        ),
+    ]

readthedocs/oauth/models.py

@@ -1,15 +1,11 @@
-# -*- coding: utf-8 -*-
-
 """OAuth service models."""
 
+from allauth.socialaccount.models import SocialAccount
 from django.contrib.auth.models import User
 from django.core.validators import URLValidator
 from django.db import models
-from django.db.models import Q
 from django.urls import reverse
 from django.utils.translation import ugettext_lazy as _
-
-from allauth.socialaccount.models import SocialAccount
 from django_extensions.db.models import TimeStampedModel
 
 from readthedocs.projects.constants import REPO_CHOICES
@@ -36,7 +32,12 @@ class RemoteOrganization(TimeStampedModel):
     slug = models.CharField(_('Slug'), max_length=255)
     name = models.CharField(_('Name'), max_length=255, null=True, blank=True)
     email = models.EmailField(_('Email'), max_length=255, null=True, blank=True)
-    avatar_url = models.URLField(_('Avatar image URL'), null=True, blank=True)
+    avatar_url = models.URLField(
+        _('Avatar image URL'),
+        null=True,
+        blank=True,
+        max_length=255,
+    )
     url = models.URLField(
         _('URL to organization page'),
         max_length=200,
@@ -140,6 +141,7 @@ class RemoteRepository(TimeStampedModel):
         _('Owner avatar image URL'),
         null=True,
         blank=True,
+        max_length=255,
     )
 
     ssh_url = models.URLField(