CC Ontologies possessive form

Added an apostrophe to "Common Core Ontologies GitHub" in line 75 as recommended by @alanruttenberg

Author: oliviahobai

documentation/contributing/github overview.md

@@ -72,7 +72,7 @@ When working with branches, you can use a **pull request** to tell others about
 
 ## Github Workflow 
 
-To illustrate, suppose you want to edit a file from the Common Core Ontologies GitHub. You should then 'fork' the develop branch of the CCO repository on your personal Github account, so that you can make whatever changes you like.  
+To illustrate, suppose you want to edit a file from the Common Core Ontologies' GitHub. You should then 'fork' the develop branch of the CCO repository on your personal Github account, so that you can make whatever changes you like.  
 
 When you make changes to your personal Github CCO repository then go to save them in GitHub, you will be prompted to either "commit to the main branch' or "create a new branch for this request and start a pull request". You should almost always open a 'pull request'. By opening a pull request, you open the door for your peers to help you refine the submission. That in mind, when you open a pull request, it is good practice to tag others and request they review your work. Once your reviewers have 'approved' your work, you will then 'merge' your work to your personal repository.