Update README.md with checkout instructions

README.md

@@ -28,7 +28,7 @@ You would need to download and install the following components for to use HPVM.
 Checkout HPVM:
 ```shell
 git clone https://gitlab.engr.illinois.edu/llvm/hpvm.git
-git checkout hpvm-reorg-9 (this step may not be needed once code is mirrored on Github)
+git checkout hpvm-release
 ```
 
 HPVM installer script can be used to download, configure and build HPVM along with LLVM and other subprojects including Clang.