simplify getting prerelease Cython for free-threaded tests

set pip environment variables

.github/workflows/test.yml

@@ -139,10 +139,11 @@ jobs:
  echo $PATH
  echo "PATH=$PATH" >> "$GITHUB_ENV"
  echo "PYTHON_GIL=0" >> "$GITHUB_ENV"
+ # need prerelease Cython until 3.1 is out
+ echo "PIP_PRE=1" >> "$GITHUB_ENV"
+ echo "PIP_EXTRA_INDEX_URL=https://pypi.anaconda.org/scientific-python-nightly-wheels/simple" >> "$GITHUB_ENV"
  shell: micromamba-shell {0}
 
-
-
  - name: setup coverage
  if: startsWith(matrix.python, 'pypy') || startsWith(matrix.python, '3.12')
  run: |
@@ -158,17 +159,6 @@ jobs:
  run: |
  pip install --upgrade pip wheel
  pip install -r test-requirements.txt
- 
- - name: install free-threading dependencies
- if: ${{ matrix.free_threading }}
- run: |
- conda info
- which -a python
- which -a pip
- # need build deps for no-build-isolation
- # remove after Cython 3.1
- pip install scikit-build-core ninja packaging
- pip install --upgrade --pre -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple cython
 
  - name: remove tornado
  if: matrix.tornado == 'none'
@@ -222,15 +212,9 @@ jobs:
  echo ZMQ_DRAFT_API=1 >> "$GITHUB_ENV"
 
  - name: build pyzmq
- if: ${{ !matrix.free_threading }}
  run: |
  pip install -v -e .
 
- - name: build pyzmq (free threading)
- if: ${{ matrix.free_threading }}
- run: |
- pip install -v --no-build-isolation .
-
  - name: import zmq
  run: |
  python -I -c "import zmq"