ci: avoid building numpy

.github/workflows/python.yml

@@ -286,7 +286,7 @@ jobs:
         run: |
           echo "PRE=$PRE"
           python -m pip install setuptools wheel nose2
-          python -m pip install $PRE setuptools_dso>=2.1a1 epicscorelibs>=7.0.3.99.2.0a1
+          python -m pip install --only-binary numpy $PRE setuptools_dso>=2.1a1 epicscorelibs>=7.0.3.99.2.0a1
           python setup.py sdist --formats=gztar
           ls dist/*
 
@@ -305,7 +305,7 @@ jobs:
           which python
           python -m pip install -U pip
           python -m pip install setuptools wheel nose2
-          python -m pip install $PRE setuptools_dso>=2.1a1 epicscorelibs>=7.0.3.99.2.0a1
+          python -m pip install --only-binary numpy $PRE setuptools_dso>=2.1a1 epicscorelibs>=7.0.3.99.2.0a1
 
           python -m pip wheel -v -w dist dist/pvxslibs-*.tar.gz