Update version comments

Author: deliahu

docs/clusters/management/update.md

@@ -56,6 +56,8 @@ This will create a CLI environment named `cortex2` for accessing the new cluster
 
 If you are spinning a up a new cluster with a different Cortex version, first install the cortex CLI matching the desired cluster version:
 
+<!-- CORTEX_VERSION_README x2 -->
+
 ```bash
 # download the desired CLI version, replace 0.38.0 with the desired version (Note the "v"):
 bash -c "$(curl -sS https://github.com/raw/cortexlabs/cortex/v0.38.0/get-cli.sh)"
@@ -69,6 +71,8 @@ cortex cluster up cluster.yaml --configure-env cortex2
 
 You can use different Cortex CLIs to interact with the different versioned clusters; here is an example:
 
+<!-- CORTEX_VERSION_README x4 -->
+
 ```bash
 # download the desired CLI version, replace 0.38.0 with the desired version (Note the "v"):
 CORTEX_INSTALL_PATH=$(pwd)/cortex0.38.0 bash -c "$(curl -sS https://github.com/raw/cortexlabs/cortex/v0.38.0/get-cli.sh)"

docs/start.md

@@ -2,7 +2,7 @@
 
 ## Create a cluster on your AWS account
 
-<!-- CORTEX_VERSION_README x2 -->
+<!-- CORTEX_VERSION_README -->
 ```bash
 # install the CLI
 bash -c "$(curl -sS https://github.com/raw/cortexlabs/cortex/v0.38.0/get-cli.sh)"