Correct version before publish

As mentioned in https://www.elastic.co/guide/en/logstash/current/_how_to_write_a_logstash_filter_plugin.html#_publishing_to_ulink_url_http_rubygems_org_rubygems_org_ulink_3

logstash-filter-date_formatter.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-filter-date_formatter'
-  s.version         = '0.0.1'
+  s.version         = '0.1.0'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "The date_formatter filter is used for formatting date or time from fields containing a time object like @timestamp, and then storing that formatted string in the field defined as target."
   s.description     = "This gem is a logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/plugin install gemname. This gem is not a stand-alone program"