CI: add minimal requirements file

.github/workflows/python-dev.yml

@@ -75,8 +75,7 @@ jobs:
         python -m pip install --upgrade pip setuptools wheel
         python -m pip install -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
         python -m pip install git+https://github.com/nedbat/coveragepy.git
-        python -m pip install versioneer[toml]
-        python -m pip install python-dateutil pytz cython hypothesis==6.52.1 pytest>=6.2.5 pytest-xdist pytest-cov pytest-asyncio>=0.17
+        python -m pip install -r ci/deps/requirements-minimal.txt pytest-cov pytest-xdist
         python -m pip list
 
     # GH 47305: Parallel build can cause flaky ImportError from pandas/_libs/tslibs

ci/deps/requirements-minimal.txt

@@ -0,0 +1,8 @@
+cython
+hypothesis==6.52.1
+numpy
+pytest>=6.2.5
+pytest-asyncio>=0.17
+python-dateutil
+pytz
+versioneer[toml]