squash: Update API_TRANSITION_GUIDE.md

Co-authored-by: Lance Ball <[email protected]>

Author: lholmquist

API_TRANSITION_GUIDE.md

@@ -5,7 +5,7 @@ When APIs are deprecated, the following guide will show how to transition from r
 
 ### Upgrading From 3.x to 4.0
 
-In the 3.2.0 release, a few API's were set to be deprecated in the 4.0 release.  With the release of 4.0.0,  those API's have been removed.
+In the 3.2.0 release, a few APIs were set to be deprecated in the 4.0 release.  With the release of 4.0.0,  those APIs have been removed.
 
 #### Receiever