[versions] change gem to 4.2.7, print c-lib version on build

[AO-9956]

Author: prettycoder

Rakefile

@@ -96,6 +96,7 @@ task :fetch_ext_deps do
   open(remote_file, 'rb') do |rf|
     content = rf.read
     File.open(local_file, 'wb') { |f| f.puts content }
+    puts "!!!!!!! C-Lib VERSION: #{content} !!!!!!!!"
   end
 
   # oboe and bson header files

lib/appoptics_apm/version.rb

@@ -8,7 +8,7 @@ module AppOpticsAPM
   module Version
     MAJOR = 4
     MINOR = 2
-    PATCH = 6
+    PATCH = 7
 
     STRING = [MAJOR, MINOR, PATCH].compact.join('.')
   end