Simplify circleci (#31)

Author: psykzz

.circleci/config.yml

@@ -3,15 +3,14 @@ version: 2
 jobs:
   build:
     docker:
-      - image: circleci/python:3.6.4
+      - image: circleci/python:3
 
     steps:
       - checkout
 
       - restore_cache:
           keys:
-          - v1-dependencies-{{ checksum "requirements.txt" }}
-          - v1-dependencies-
+          - deps-{{ checksum "requirements.txt" }}
 
       - run:
           name: install dependencies
@@ -23,7 +22,7 @@ jobs:
       - save_cache:
           paths:
             - ./venv
-          key: v1-dependencies-{{ checksum "requirements.txt" }}
+          key: deps-{{ checksum "requirements.txt" }}
 
       - run:
           name: run linting and metrics
@@ -34,4 +33,4 @@ jobs:
 
       - store_artifacts:
           path: test-reports
-          destination: test-reports
+          destination: test-reports