README.md in signet-0.17.0 vs README.md in signet-0.18.0

@@ -57,13 +57,13 @@
 
 Be sure `https://rubygems.org` is in your gem sources.
 
 ## Supported Ruby Versions
 
-This library is supported on Ruby 2.5+.
+This library is supported on Ruby 2.6+.
 
 Google provides official support for Ruby versions that are actively supported
-by Ruby Core—that is, Ruby versions that are either in normal maintenance or in
-security maintenance, and not end of life. Currently, this means Ruby 2.5 and
-later. Older versions of Ruby _may_ still work, but are unsupported and not
-recommended. See https://www.ruby-lang.org/en/downloads/branches/ for details
-about the Ruby support schedule.
+by Ruby Core—that is, Ruby versions that are either in normal maintenance or
+in security maintenance, and not end of life. Older versions of Ruby _may_
+still work, but are unsupported and not recommended. See
+https://www.ruby-lang.org/en/downloads/branches/ for details about the Ruby
+support schedule.