ZOOKEEPER-3960: Update Programmers Guide about key file format parameters

The Programmer's guide doesn't contain the parameters needed to be changed in order to specify keystore and truststore file formats for the Java Clients.
see: https://zookeeper.apache.org/doc/r3.6.2/zookeeperProgrammers.html#sc_java_client_configuration

Author: Mate Szalay-Beko <symat@apache.org>

Reviewers: Enrico Olivelli <eolivelli@apache.org>, Norbert Kalmar <nkalmar@apache.org>

Closes #1488 from symat/zookeeper-3960

zookeeper-docs/src/main/resources/markdown/zookeeperProgrammers.md

@@ -1320,6 +1320,7 @@ and [SASL authentication for ZooKeeper](https://cwiki.apache.org/confluence/disp
     this behavior by setting zookeeper.disableAutoWatchReset to **true**.
 
 * *zookeeper.client.secure* :
+    **New in 3.5.5:**
     If you want to connect to the server secure client port, you need to set this property to
     **true**
     on the client. This will connect to server using SSL with specified credentials. Note that
@@ -1337,13 +1338,22 @@ and [SASL authentication for ZooKeeper](https://cwiki.apache.org/confluence/disp
     on client.
 
 * *zookeeper.ssl.keyStore.location and zookeeper.ssl.keyStore.password* :
+    **New in 3.5.5:**
     Specifies the file path to a JKS containing the local credentials to be used for SSL connections,
     and the password to unlock the file.
 
 * *zookeeper.ssl.trustStore.location and zookeeper.ssl.trustStore.password* :
+    **New in 3.5.5:**
     Specifies the file path to a JKS containing the remote credentials to be used for SSL connections,
     and the password to unlock the file.
 
+* *zookeeper.ssl.keyStore.type* and *zookeeper.ssl.trustStore.type*:
+    **New in 3.5.5:**
+    Specifies the file format of keys/trust store files used to establish TLS connection to the ZooKeeper server. 
+    Values: JKS, PEM, PKCS12 or null (detect by filename). Default: null.
+    **New in 3.6.3, 3.7.0:**
+    The format BCFKS was added.
+
 * *jute.maxbuffer* :
     In the client side, it specifies the maximum size of the incoming data from the server. The default is 0xfffff(1048575) bytes,
     or just under 1M. This is really a sanity check. The ZooKeeper server is designed to store and send