Bump to 3.4.5

Fixes #126

Author: andrewvc

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.4.5
+  - Major performance improvements due to reduced locking
+
 ## 3.4.4
   - Update gemspec summary
 

logstash-filter-grok.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-filter-grok'
-  s.version         = '3.4.4'
+  s.version         = '3.4.5'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Parses unstructured event data into fields"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"