Stage requirements.txt into its own file. (#2501)

Co-authored-by: Paul Fisher <[email protected]>

.github/workflows/python-so-copying.yml

@@ -309,6 +309,8 @@ jobs:
           otool -L ./venv-soma/lib/python*/site-packages/tiledbsoma/pytiledbsoma.*.so
           otool -l ./venv-soma/lib/python*/site-packages/tiledbsoma/pytiledbsoma.*.so
       - name: Install runtime dependencies
-        run: ./venv-soma/bin/python -m pip install --prefer-binary `grep -v '^\[' apis/python/src/tiledbsoma.egg-info/requires.txt`
+        run: |
+          grep -v '^\[' apis/python/src/tiledbsoma.egg-info/requires.txt >/tmp/filtered-requirements.txt
+          ./venv-soma/bin/pip install --prefer-binary -r /tmp/filtered-requirements.txt
       - name: Runtime test
         run: ./venv-soma/bin/python -c "import tiledbsoma; print(tiledbsoma.pytiledbsoma.version())"