Switch default branch to main from master

The former is quickly becoming the conventional choice and by
switching wsproto will likely match other projects the maintainers
use.

Author: pgjones

.github/workflows/ci.yml

@@ -2,9 +2,9 @@ name: CI
 
 on:
   push:
-    branches: ["master"]
+    branches: ["main"]
   pull_request:
-    branches: ["master"]
+    branches: ["main"]
 
 jobs:
   tox:

README.rst

@@ -5,7 +5,7 @@ Pure Python, pure state-machine WebSocket implementation
 .. image:: https://github.com/python-hyper/wsproto/workflows/CI/badge.svg
     :target: https://github.com/python-hyper/wsproto/actions
     :alt: Build Status
-.. image:: https://codecov.io/gh/python-hyper/wsproto/branch/master/graph/badge.svg
+.. image:: https://codecov.io/gh/python-hyper/wsproto/branch/main/graph/badge.svg
     :target: https://codecov.io/gh/python-hyper/wsproto
     :alt: Code Coverage
 .. image:: https://readthedocs.org/projects/wsproto/badge/?version=latest

docs/source/basic-usage.rst

@@ -121,7 +121,7 @@ the data currently in the ``wsproto`` internal buffer and then exit. Therefore,
 you should iterate over this generator after receiving new network data.
 
 For a more complete example, see `synchronous_client.py
-<https://github.com/python-hyper/wsproto/blob/master/example/synchronous_client.py>`_.
+<https://github.com/python-hyper/wsproto/blob/main/example/synchronous_client.py>`_.
 
 WebSocket Servers
 -----------------
@@ -150,7 +150,7 @@ Alternatively a server can explicitly reject the connection by sending
 receiving a ``Request`` event.
 
 For a more complete example, see `synchronous_server.py
-<https://github.com/python-hyper/wsproto/blob/master/example/synchronous_server.py>`_.
+<https://github.com/python-hyper/wsproto/blob/main/example/synchronous_server.py>`_.
 
 Protocol Errors
 ---------------