[CI] Add/update 'rake install', update Psych version for Ruby 3.1 gem install

Author: MSP-Greg

.github/workflows/macos.yml

@@ -21,3 +21,6 @@ jobs:
         run: bundle install
       - name: Run test
         run: rake
+      - name: Install gem
+        run: rake install
+        if: ${{ matrix.ruby != 'head' }}

.github/workflows/ubuntu.yml

@@ -23,4 +23,4 @@ jobs:
         run: rake
       - name: Install gem
         run: rake install
-        if: ${{ matrix.ruby != 'head' && matrix.ruby != '3.1' }}
+        if: ${{ matrix.ruby != 'head' }}

.github/workflows/windows.yml

@@ -21,3 +21,8 @@ jobs:
         run: bundle install
       - name: Run test
         run: rake
+      - name: Install gem
+        run: rake install
+        # use all possible head strings
+        if: |
+          !(contains('ucrt mingw mswin head', matrix.ruby))

lib/psych/versions.rb

@@ -2,7 +2,7 @@
 
 module Psych
   # The version of Psych you are using
-  VERSION = '4.0.3'
+  VERSION = '4.0.4.dev'
 
   if RUBY_ENGINE == 'jruby'
     DEFAULT_SNAKEYAML_VERSION = '1.28'.freeze