ci.yml: remove cygwin (broken, see sagemath#218)

Author: tornaria

.github/workflows/ci.yml

@@ -51,37 +51,6 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  cygwin:
-    runs-on: windows-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        python-version-start: [python-3]
-        python-version: [9]
-    steps:
-    - run: |
-        git config --global core.autocrlf false
-        git config --global core.symlinks true
-    - name: Set up the repository
-      uses: actions/checkout@v4
-      with:
-          submodules: recursive
-          fetch-depth: 0
-    - name: Set up Cygwin
-      uses: egor-tensin/setup-cygwin@v4
-      with:
-        packages: gcc-core gcc-g++ python3${{ matrix.python-version }}-devel ninja pkgconf
-    - name: Install dependencies
-      shell: C:\tools\cygwin\bin\bash.exe --norc -eo pipefail -o igncr '{0}'
-      run: |
-        python3.${{ matrix.python-version }} -m pip install --upgrade pip
-        python3.${{ matrix.python-version }} -m pip install --upgrade -r ./requirements.txt
-    - name: Build and check
-      shell: C:\tools\cygwin\bin\bash.exe --norc -eo pipefail -o igncr '{0}'
-      run: |
-        pip install --no-build-isolation --config-settings=builddir=builddir .
-        meson test --print-errorlogs -C builddir
-
   ci:
     name: CI (${{ matrix.os }} with Python ${{ matrix.python-version }})
     runs-on: ${{ matrix.os }}