[minor] chore: add make test recipe, use make test in CI

Author: fquffio

.travis.yml

@@ -1,12 +1,12 @@
 sudo: false
 
-language: python
+language: 'python'
 
 install:
   - 'pip install awscli'
 
 script:
-  - 'for template in $(ls *.yml); do aws cloudformation validate-template --template-body file://$template; done'
+  - 'make test'
 
 before_deploy:
   - 'mkdir -p templates'

Makefile

@@ -1,4 +1,9 @@
-.PHONY: list-instance-types list-latest-amis
+.PHONY: list-instance-types list-latest-amis test
+
+test:
+	@for template in $$(ls *.yml); do \
+		aws cloudformation validate-template --template-body file://$$template; \
+	done
 
 list-instance-types:
 	@instance_types=$$( \