chore(aws-lambda) remove Makefile, update KONG_TAG and add Travis C…

…I badge (#7)

* chore(aws-lambda) remove Makefile

* chore(aws-lambda) update `KONG_TAG`

* docs(aws-lambda) re-add Travis CI badge

.travis.yml

@@ -25,7 +25,7 @@ env:
     - CASSANDRA_BASE=2.2.12
     - CASSANDRA_LATEST=3.9
     - KONG_REPOSITORY=kong
-    - KONG_TAG=master
+    - KONG_TAG=next
     - DOWNLOAD_CACHE=$HOME/download-cache
     - INSTALL_CACHE=$HOME/install-cache
     - DOWNLOAD_ROOT=$HOME/download-root

README.md

@@ -1,3 +1,5 @@
+[![Build Status][badge-travis-image]][badge-travis-url]
+
 # kong-plugin-aws-lambda
 
 Invoke an [AWS Lambda](https://aws.amazon.com/lambda/) function from Kong. It can be used in combination with other request plugins to secure, manage or extend the function.
@@ -135,3 +137,6 @@ Here's a list of all the parameters which can be used in this plugin's configura
 ## Notes
 
 When the IAM roles are used (default, if no `aws.key` / `aws.secret` is provided), the plugin will first try ECS metadata, and if not available it will fallback on EC2 metadata.
+
+[badge-travis-image]: https://travis-ci.com/Kong/kong-plugin-aws-lambda.svg?branch=master
+[badge-travis-url]: https://travis-ci.com/Kong/kong-plugin-aws-lambda