stellar#41, added docs on js client version

Makefile

@@ -21,6 +21,7 @@ SOROBAN_RPC_GIT_REF=https://github.com/stellar/soroban-tools.git\#main
 SOROBAN_CLI_GIT_REF=https://github.com/stellar/soroban-tools.git\#main
 GO_GIT_REF=https://github.com/stellar/go.git\#soroban-xdr-next
 QUICKSTART_GIT_REF=https://github.com/stellar/quickstart.git\#master
+# specify the published npm repo version of soroban-client js library, or you can specify gh git ref url as the version also
 JS_SOROBAN_CLIENT_NPM_VERSION=https://github.com/stellar/js-soroban-client.git\#main
 
 # variables to set if wanting to use existing dockerhub images instead of compiling

README.md

@@ -21,7 +21,7 @@ To run tests, requires two steps:
        build     
   ```  
 
-  example of build using specific git branches, latest in this case, or use tag names for releases:  
+  example of build using specific git refs, mainline from repos in this example, or use tags, branches, etc:  
   ```
   $ make CORE_GIT_REF=https://github.com/stellar/stellar-core.git#f1dc39f0f146815e5e3a94ed162e2f0639cb433f \
          CORE_COMPILE_CONFIGURE_FLAGS="--disable-tests --enable-next-protocol-version-unsafe-for-production" \
@@ -60,6 +60,11 @@ To run tests, requires two steps:
   # this will override the default Node JS vm version used for running the JS code:
   NODE_VERSION=14.20.0
 
+  # soroban js client version can be set to a published npm version on https://www.npmjs.com/package/soroban-client 
+  JS_SOROBAN_CLIENT_NPM_VERSION=latest
+  # or it can be set to a github git ref of a js-soroban-client repo
+  JS_SOROBAN_CLIENT_NPM_VERSION=https://github.com/stellar/js-soroban-client.git\#main
+
   # Image overrides. 
   # If using these, the image ref should provide a manifiest version for same 
   # platform arch as the build host is running on, i.e. linux/amd64 or linux/arm64.