Drop Ruby 2.3.x support

Author: ixti

.travis.yml

@@ -18,7 +18,6 @@ env: JRUBY_OPTS="$JRUBY_OPTS --debug"
 rvm:
   # Include JRuby first because it takes the longest
   - jruby-9.2.5.0
-  - 2.3
   - 2.4
   - 2.5
   - 2.6

CHANGES.md

@@ -22,6 +22,9 @@
   Provide initiating `HTTP::Request` object on `HTTP::Response`.
   ([@joshuaflanagan])
 
+* Drop Ruby 2.3.x support.
+  ([@ixti])
+
 
 ## 4.1.1 (2019-03-12)
 

README.md

@@ -164,7 +164,6 @@ and call `#readpartial` on it repeatedly until it returns `nil`:
 This library aims to support and is [tested against][travis] the following Ruby
 versions:
 
-* Ruby 2.3.x
 * Ruby 2.4.x
 * Ruby 2.5.x
 * Ruby 2.6.x