Fixed the CI/CD configuration.

I have dev_requirements.txt for tests, not requirements.txt

.drone.yaml

@@ -6,6 +6,6 @@ steps:
 - name: install dependencies and run tests
   image: python:3.10-alpine
   commands:
-  - pip install -r requirements.txt
+  - pip install -r dev_requirements.txt
   - pytest -s