Merge pull request #25 from signalsciences/lisa/updated-readme

Updated README.md with branch name change notice

Author: lsmith500

README.md

@@ -9,6 +9,16 @@ level. It is written as a `http.Handler` wrapper. To
 integrate your application with the module, you will need to wrap your
 existing handler with the module handler.
 
+## :rotating_light: NOTICE :rotating_light:
+
+Effective **May 17th 2021** the default branch will change from `master` to `main`. Run the following commands to update a local clone:
+```
+git branch -m master main
+git fetch origin
+git branch -u origin/main main
+git remote set-head origin -
+```
+
 ## Installation
 `go get github.com/signalsciences/sigsci-module-golang`