Fix branch names

Author: frozencemetery

.github/workflows/deploy-docs.yml

@@ -1,6 +1,6 @@
 {
     "name": "Deploy docs",
-    "on": { "push": { "branches": "master" }},
+    "on": { "push": { "branches": "main" }},
     "jobs": {
         "update-pages": {
             "runs-on": "ubuntu-latest",

README.txt

@@ -22,7 +22,7 @@ Documentation for the latest released version (including pre-release versions)
 can be found at
 `https://pythongssapi.github.io/python-gssapi/stable <https://pythongssapi.github.io/python-gssapi/stable>`_.
 
-Documentation for the latest commit on master can be found at
+Documentation for the latest commit on main can be found at
 `https://pythongssapi.github.io/python-gssapi/latest <https://pythongssapi.github.io/python-gssapi/latest>`_.
 
 Requirements