Keep version pins in .pip files

Author: nedbat

.github/workflows/kit.yml

@@ -32,7 +32,7 @@ jobs:
 
       - name: Install cibuildwheel
         run: |
-          python -m pip install cibuildwheel==1.7.0
+          python -m pip install -c requirements/pins.pip cibuildwheel
 
       - name: Install Visual C++ for Python 2.7
         if: runner.os == 'Windows'

.github/workflows/testsuite.yml

@@ -43,6 +43,7 @@ jobs:
           python -VV
           python -m site
           python -m pip install -r requirements/ci.pip
+          python -m pip install -c requirements/pins.pip tox-gh-actions
 
       - name: "Run tox for ${{ matrix.python-version }}"
         shell: bash

requirements/ci.pip

@@ -1,8 +1,7 @@
 # Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
 # For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
 
-# Things CI servers need to succeeed.
+# Things CI servers need for running tests.
 -r tox.pip
 -r pytest.pip
 -r wheel.pip
-tox-gh-actions==2.2.0

requirements/pins.pip

@@ -0,0 +1,7 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
+
+# Version pins, for use as a constraints file.
+
+cibuildwheel==1.7.0
+tox-gh-actions==2.2.0