fix typo in workflow slide

2022/2022-06-07_git-trilogy-part-2/slides/workflow.md

@@ -2,7 +2,7 @@
 
 - Create your own copy of the original (also called `upstream`) repository (`fork` in `git` jargon)
 - Download your copy to your computer (`clone` in `git` jargon)
-- Create a new brach
+- Create a new branch
 - Make changes
 - Commit changes
 - <font color="red">Push changes to server</font>