Fix all Docker image build and push issues (#433)

* Put all commands in one line, add skip_cleanup flag

* Add more secure Docker login, fix wrong push tag

Author: Jonatas Baldin

.travis.yml

@@ -14,9 +14,8 @@ script:
   - make test
 deploy:
   provider: script
-  script:
-    - make docker-build
-    - make docker-push
+  script: make docker-build && make docker-push
+  skip_cleanup: true
   on:
     tags: true
     python: "3.6"

Makefile

@@ -53,6 +53,6 @@ docker-build:
 	docker tag twilio/twilio-python twilio/twilio-python:apidefs-${API_DEFINITIONS_SHA}
 
 docker-push:
-	docker login -u ${DOCKER_USERNAME} -p ${DOCKER_PASSWORD}
+	echo ${DOCKER_PASSWORD} | docker login -u ${DOCKER_USERNAME} --password-stdin
 	docker push twilio/twilio-python:${TRAVIS_TAG}
-	docker push twilio/twilio-python:apidefs-${API_DEFINITIONS_TAG}
+	docker push twilio/twilio-python:apidefs-${API_DEFINITIONS_SHA}