Update README.md

Author: mrosseel

README.md

@@ -2,7 +2,7 @@
 
 We ran into the issue that our Wiki got stale and became unmaintainable. After several failed attempts at making something better, we settled on mkdocs hosted on Github Pages. 
 
-The mkdocs site should be automatically be rebuild on push to main. Just add/update your pages and push.
+The mkdocs site should be automatically be rebuilt on push to main. Just add/update your pages and push.
 
 ## Steps to edit content
 ### Option 1: quick edit