Update README.md

README.md

 # Repository holding the sources of the KWARC.info website
 
-** Building this page can take up to two minutes. This is normal and to be expected. **
+**Building this page can take up to five minutes. This is normal and to be expected.**
 
 Note for authors: When editing some text, please do not hard wrap existing lines. 
 This plays very bad with diffs, in particular an entire paragraph shows up as changed even though it might just be a single line.