[ruby/pp] Bump version to 0.4.0

https://github.com/ruby/pp/commit/8870aa02df
2022-12-05 16:21:07 +09:00 · 2022-12-05 16:21:07 +09:00 · 7a7d1b3853
--- a/lib/pp.gemspec
+++ b/lib/pp.gemspec
@ -1,6 +1,6 @@
 Gem::Specification.new do |spec|
  spec.name          = "pp"
-  spec.version       = "0.3.0"
+  spec.version       = "0.4.0"
  spec.authors       = ["Tanaka Akira"]
  spec.email         = ["akr@fsij.org"]