Require tox < 3.1 to avoid basepython conflicts

diff --git a/project_template/appveyor.yml b/project_template/appveyor.yml
index 107899846ff9fa5b4f97f1f360a305cc398a2556..7c06e215c023ffb302f25133a4b4fcb3ea86e358 100644 (file)
--- a/project_template/appveyor.yml
+++ b/project_template/appveyor.yml
@@ -72,7 +72,7 @@ install:
   - "python --version"
   - "python -c \"import struct; print(struct.calcsize('P') * 8)\""
   - "python -m pip install --upgrade pip setuptools"
-  - "pip install --upgrade tox ppu"
+  - "pip install --upgrade \"tox < 3.1\" ppu"
   - "pip --version"
 
 # No build step - we don't have C extensions