fix: add condition for using steep and typeprof to pass CI with all Ruby versions

As a first step toward adopting rbs for this project, added type a definition for a simple method.
More type definitions will be added incrementally.

.github/FUNDING.yml

@@ -0,0 +1 @@
+ko_fi: kojix2

.github/dependabot.yml

@@ -1,6 +0,0 @@
-version: 2
-updates:
-- package-ecosystem: "github-actions"
-  directory: "/"
-  schedule:
-    interval: "weekly"

.github/workflows/ci.yml

@@ -7,9 +7,9 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu", "macos"]
-        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4", "head"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}

.github/workflows/doc.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ruby

Gemfile

@@ -5,6 +5,13 @@ source 'https://rubygems.org'
 # Specify your gem's dependencies in youplot.gemspec
 gemspec
 
+group :development do
+  if RUBY_VERSION >= '3.0'
+    gem 'steep', require: false
+    gem 'typeprof'
+  end
+end
+
 group :test do
   gem 'rake'
   gem 'simplecov'

LICENSE.txt

@@ -1,7 +1,6 @@
 The MIT License (MIT)
 
 Copyright (c) 2020 kojix2
-Copyright (c) 2025 Red Data Tools
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -311,7 +311,7 @@ bundle exec exe/uplot      # Run youplot (Try out the edited code)
 
 ### Acknowledgements
 
-* [sampo grafiikka](https://lepo.sampo-grafiikka.com/) - Project logo creation
+* [sampo grafiikka](https://jypg.net/sampo_grafiikka) - Project logo creation
 * [yutaas](https://github.com/yutaas) - English proofreading
 
 ## License

Steepfile

@@ -0,0 +1,8 @@
+D = Steep::Diagnostic
+
+target :lib do
+  signature "sig"
+  check "lib" # Directory name to check
+
+  configure_code_diagnostics(D::Ruby.silent) # `silent` diagnostics setting
+end

sig/youplot/backends/processing.rbs

@@ -0,0 +1,7 @@
+module YouPlot
+  module Backends
+    module Processing
+      def count_values: ([], ?tally: true, ?reverse: false) -> Array[Array[untyped]]
+    end
+  end
+end