CI: mingw: Use the official actions for msys2

Because ruby/setup-ruby is affected to test result.

.github/workflows/mingw.yml

@@ -65,10 +65,21 @@ jobs:
       )}}
 
     steps:
-      - name: Set up Ruby & MSYS2
-        uses: ruby/setup-ruby@d8d83c3960843afb664e821fed6be52f37da5267 # v1.231.0
+      - uses: msys2/setup-msys2@40677d36a502eb2cf0fb808cc9dec31bf6152638 # v2.28.0
+        id: msys2
         with:
-          ruby-version: '3.2'
+          msystem: UCRT64
+          update: true
+          install: >-
+            git
+            make
+            ruby
+            autoconf
+            mingw-w64-ucrt-x86_64-gcc
+            mingw-w64-ucrt-x86_64-ragel
+            mingw-w64-ucrt-x86_64-openssl
+            mingw-w64-ucrt-x86_64-libyaml
+            mingw-w64-ucrt-x86_64-libffi
 
       - name: Set up env
         id: setup-env
@@ -86,7 +97,7 @@ jobs:
             Tee-Object ${env:GITHUB_ENV} -Append -Encoding utf-8
         shell: pwsh             # cmd.exe does not strip spaces before `|`.
         env:
-          MSYS2_LOCATION: ${{ env.RI_DEVKIT }}
+          MSYS2_LOCATION: ${{ steps.msys2.outputs.msys2-location }}
 
       - name: Remove Strawberry Perl pkg-config
         working-directory: