Update v8 version for security purpose

Author: pinepain

Diff for: README.md

@@ -100,7 +100,7 @@ on top of php-v8 extension and makes embedding JavaScript in PHP easier.
 ### Requirements
 
 #### V8
-You will need a recent v8 Google JavaScript engine version installed. At this time v8 >= 6.5.116 required.
+You will need a recent v8 Google JavaScript engine version installed. At this time v8 >= 6.5.144 required.
 
 #### PHP
 This extension is PHP7-only. It works and tested with both PHP 7.0 and PHP 7.1.

Diff for: config.m4

@@ -19,7 +19,7 @@ if test "$PHP_V8" != "no"; then
   SEARCH_PATH="/usr/local /usr"
   SEARCH_FOR="include/v8.h"
 
-  V8_MIN_API_VERSION_STR=6.5.116
+  V8_MIN_API_VERSION_STR=6.5.144
 
   DESIRED_V8_VERSION=`echo "${V8_MIN_API_VERSION_STR}" | $AWK 'BEGIN { FS = "."; } { printf "%s.%s", [$]1, [$]2;}'`