Add flake8 and vermin to tests make command

.flake8

@@ -1,4 +1,4 @@
 [flake8]
-exclude=build,tests
+exclude=build,tests,tmp
 ignore=E128
 max-line-length=120

Makefile

@@ -9,6 +9,8 @@ publish :
 
 test:
 	pytest -v
+	flake8
+	vermin --target=3.6 --no-tips --violations .
 
 coverage:
 	coverage erase