Merge pull request #30 from stanley-cheung/update-to-1_42

Update to v1.42.0

Author: stanley-cheung

composer.json

@@ -5,7 +5,7 @@
   "keywords": ["rpc"],
   "homepage": "https://grpc.io",
   "license": "Apache-2.0",
-  "version": "1.39.0",
+  "version": "1.42.0",
   "require": {
     "php": ">=7.0.0"
   },