Add note about marshmallow 3
@@ -29,6 +29,8 @@ requirements:
- semantic_version >=2.8.1
- tabulate >=0.8.3
- pyelftools >=0.25
+ # They truely don't support marshmallow 3
+ # https://github.com/platformio/platformio-core/pull/3296
- marshmallow >=2.20.5,<3
test:
