Bump cpp client version to 3.4.2 (#361)

pulsar-client-cpp.txt

diff --git a/pulsar-client-cpp.txt b/pulsar-client-cpp.txt
index 2d99b9e..4433d6e 100644
--- a/pulsar-client-cpp.txt
+++ b/pulsar-client-cpp.txt
@@ -1,2 +1,2 @@
-CPP_CLIENT_BASE_URL=https://archive.apache.org/dist/pulsar/pulsar-client-cpp-3.4.1
-CPP_CLIENT_VERSION=3.4.1
+CPP_CLIENT_BASE_URL=https://archive.apache.org/dist/pulsar/pulsar-client-cpp-3.4.2
+CPP_CLIENT_VERSION=3.4.2