migrate CI to new official Windows opam 2.3

.github/workflows/windows.yaml

@@ -4,21 +4,29 @@ on:
   workflow_dispatch:
 jobs:
   build:
-    runs-on: [self-hosted, windows, X64]
+    runs-on: [self-hosted, windows, X64, opam-2-3]
     steps:
       - name: Check out repo        
-        uses: actions/checkout@v2
-      - name: Build EverParse and its dependencies
-        shell: powershell
+        uses: actions/checkout@v4
+      - name: Build EverParse
+        shell: C:\cygwin64\bin\bash.exe --login '{0}'
         run: |
-          .\src\package\windows\build-everparse.ps1 -WithClean -DownloadZ3
-      - name: Test EverParse
-        shell: cmd
-        run: |
-          .\everparse\everparse.cmd src\3d\tests\Arithmetic.3d src\3d\tests\FieldDependence0.3d && .\everparse\everparse.cmd src\3d\tests\Comments.3d && .\everparse\everparse.cmd --check_hashes inplace src\3d\tests\Comments.3d
+          eval $(opam env) && CC=x86_64-w64-mingw32-gcc.exe make -C $GITHUB_WORKSPACE -j 8 everparse && echo "There is a CR at the end of this line"
       - name: Archive EverParse package
         uses: actions/upload-artifact@v4
         with:
           name: everparse
           path: everparse
           include-hidden-files: true
+  test:
+    needs: build
+    runs-on: windows-latest
+    steps:
+      - name: Download and extract artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: everparse
+      - name: Test EverParse
+        shell: cmd
+        run: |
+          .\everparse\everparse.cmd src\3d\tests\Arithmetic.3d src\3d\tests\FieldDependence0.3d && .\everparse\everparse.cmd src\3d\tests\Comments.3d && .\everparse\everparse.cmd --check_hashes inplace src\3d\tests\Comments.3d