Update README.md

Fixing a broken init command. This mistake is probably present across all branches.

README.md

@@ -47,7 +47,7 @@ familiar with [Git and Repo](https://source.android.com/source/using-repo.html).
 
 To initialize your local repository using the OMNIROM trees to build TWRP, use a command like this:
 
-    repo init -u git://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-8.1
+    repo init -u https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-8.1
     
 To initialize a shallow clone, which will save even more space, use a command like this: