Replace references of this repo's "master" branch

with "main".

Python.gitignore

@@ -139,7 +139,7 @@ cython_debug/
 
 # PyCharm
 #  JetBrains specific template is maintainted in a separate JetBrains.gitignore that can
-#  be found at https://github.com/github/gitignore/blob/master/Global/JetBrains.gitignore
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/

Umbraco.gitignore

 ## Ignore Umbraco files/folders generated for each instance
 ##
-## Get latest from https://github.com/github/gitignore/blob/master/Umbraco.gitignore
+## Get latest from https://github.com/github/gitignore/blob/main/Umbraco.gitignore
 
 # Note: VisualStudio gitignore rules may also be relevant
 

Unity.gitignore

 # This .gitignore file should be placed at the root of your Unity project directory
 #
-# Get latest from https://github.com/github/gitignore/blob/master/Unity.gitignore
+# Get latest from https://github.com/github/gitignore/blob/main/Unity.gitignore
 #
 /[Ll]ibrary/
 /[Tt]emp/

VisualStudio.gitignore

 ## Ignore Visual Studio temporary files, build results, and
 ## files generated by popular Visual Studio add-ons.
 ##
-## Get latest from https://github.com/github/gitignore/blob/master/VisualStudio.gitignore
+## Get latest from https://github.com/github/gitignore/blob/main/VisualStudio.gitignore
 
 # User-specific files
 *.rsuser

WordPress.gitignore

 # Wordpress - ignore core, configuration, examples, uploads and logs.
-# https://github.com/github/gitignore/blob/master/WordPress.gitignore
+# https://github.com/github/gitignore/blob/main/WordPress.gitignore
 
 # Core
 #