add constraints.txt

.github/workflows/python-package-conda.yml

@@ -27,10 +27,10 @@ jobs:
     - name: Install dependencies
       run: |
         conda config --set always_yes yes --set changeps1 no
-        pip install -U -r requirements.txt
+        pip install -U -r requirements.txt -c constraints.txt
     - name: Lint with pylint and pycodestyle
       run: |
-        pip install -U -r requirements-dev.txt
+        pip install -U -r requirements-dev.txt -c constraints.txt
         python setup.py build_ext --inplace
         pylint -rn mthree
         pycodestyle --max-line-length=100 mthree