Fix README auto update for preview/RC

Author: eregon

README.md

@@ -15,7 +15,7 @@ This action currently supports these versions of MRI, JRuby and TruffleRuby:
 
 | Interpreter | Versions |
 | ----------- | -------- |
-| `ruby` | 1.9.3, 2.0.0, 2.1.9, 2.2, all versions from 2.3.0 until 3.2.0-preview1, head, debug, mingw, mswin, ucrt |
+| `ruby` | 1.9.3, 2.0.0, 2.1.9, 2.2, all versions from 2.3.0 until 3.2.0-rc1, head, debug, mingw, mswin, ucrt |
 | `jruby` | 9.1.17.0 - 9.4.0.0, head |
 | `truffleruby` | 19.3.0 - 22.3.0, head |
 | `truffleruby+graalvm` | 21.2.0 - 22.3.0, head |

new-versions.rb

@@ -53,7 +53,7 @@
     file = "#{__dir__}/README.md"
     lines = File.readlines(file)
     engine_line = lines.find { |line| line.start_with?("| `#{engine}`") }
-    engine_line.sub!(/(.+ (?:-|until)) (\d+(?:\.\d+)+)/) do
+    engine_line.sub!(/(.+ (?:-|until)) (\d+(?:\.\d+)+(?:-\w+)?)/) do
       if Gem::Version.new(version) > Gem::Version.new($2)
         "#{$1} #{version}"
       else