Fix typo: 2018 -> 2019

Author: hellvinz

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 For the full commit log, [see here](https://github.com/influxdata/influxdb-ruby/commits/master).
 
-## v0.7.0, released 2018-01-11
+## v0.7.0, released 2019-01-11
 
 - Drop support for Ruby 2.2, since Bundler dropped it and we want to use
   Bundler in the development cycle as well.