[FAB-8308][sdk-node]Fix broken link in README.md

The link to fabric-ca is broken in README.md of fabric-sdk-node.
This CR updates the link correctly.

Change-Id: If8e0897bdaf01427d07404575e2f3dc4afb03b62
Signed-off-by: Yuki Kondo <[email protected]>

README.md

@@ -10,7 +10,7 @@ As an application developer, to learn about how to install and use the Node.js S
 
 This project publishes two separate npm packages:
 * `fabric-client` - main client for the [Hyperledger Fabric](http://hyperledger-fabric.readthedocs.io/en/latest/). Applications can use this package to install and instantiate chaincodes, submit transactions and make queries against a Hyperledger Fabric-based blockchain network.
-* `fabric-ca-client` - client for the optional component in Hyperledger Fabric, [fabric-ca](http://hyperledger-fabric.readthedocs.io/en/latest/Setup/ca-setup.html). The fabric-ca component allows applications to enroll Peers and application users to establish trusted identities on the blockchain network. It also provides support for pseudonymous transaction submissions with Transaction Certificates. If the target blockchain network is configured with standard Certificate Authorities for trust anchors, the application does not need to use this package.
+* `fabric-ca-client` - client for the optional component in Hyperledger Fabric, [fabric-ca](http://hyperledger-fabric-ca.readthedocs.io/en/latest/users-guide.html). The fabric-ca component allows applications to enroll Peers and application users to establish trusted identities on the blockchain network. It also provides support for pseudonymous transaction submissions with Transaction Certificates. If the target blockchain network is configured with standard Certificate Authorities for trust anchors, the application does not need to use this package.
 
 The following section targets a current or future contributor to this project itself.