update links in README and {bookwyrm,celerywyrm}/settings.py files

the link to celery's homepage has been dead for at least several months
activitypub.rocks now supports tls (yay!)
the links to django's docs were for older versions of django than what bookwyrm uses

README.md

@@ -73,8 +73,8 @@ Since the project is still in its early stages, the features are growing every d
 Web backend
 - [Django](https://www.djangoproject.com/) web server
 - [PostgreSQL](https://www.postgresql.org/) database
-- [ActivityPub](http://activitypub.rocks/) federation
-- [Celery](http://celeryproject.org/) task queuing
+- [ActivityPub](https://activitypub.rocks/) federation
+- [Celery](https://docs.celeryproject.org/) task queuing
 - [Redis](https://redis.io/) task backend
 - [Redis (again)](https://redis.io/) activity stream manager
 

bookwyrm/settings.py

@@ -166,7 +166,7 @@ USE_TZ = True
 
 
 # Static files (CSS, JavaScript, Images)
-# https://docs.djangoproject.com/en/2.0/howto/static-files/
+# https://docs.djangoproject.com/en/3.1/howto/static-files/
 
 PROJECT_DIR = os.path.dirname(os.path.abspath(__file__))
 STATIC_URL = "/static/"

celerywyrm/settings.py

@@ -149,7 +149,7 @@ USE_TZ = True
 
 
 # Static files (CSS, JavaScript, Images)
-# https://docs.djangoproject.com/en/3.0/howto/static-files/
+# https://docs.djangoproject.com/en/3.1/howto/static-files/
 
 STATIC_URL = "/static/"
 STATIC_ROOT = os.path.join(BASE_DIR, env("STATIC_ROOT", "static"))