Add editable install to requirements.txt

Author: brandonwillard

.travis.yml

@@ -8,8 +8,7 @@ python:
   - "pypy3"
 
 install:
-  - pip install -r requirements-dev.txt
-  - pip install -e ./
+  - pip install -r requirements.txt
 
 script:
   - pylint cons/ tests/

requirements-dev.txt renamed to requirements.txt

@@ -1,3 +1,4 @@
+-e ./
 coveralls
 pydocstyle>=3.0.0
 pytest>=5.0.0