readme badge update

Author: jakewmeyer

README.md

@@ -3,10 +3,10 @@
 <h1 align="center">SpaceX REST API</h1>
 
 <p align="center">
-<a href="https://travis-ci.org/r-spacex/SpaceX-API"><img src="https://img.shields.io/travis/r-spacex/SpaceX-API.svg?style=flat-square"></a>
-<a href="https://hub.docker.com/r/jakewmeyer/spacex-api/"><img src="https://img.shields.io/docker/build/jakewmeyer/spacex-api.svg?style=flat-square"></a>
-<a href="https://github.com/r-spacex/SpaceX-API/releases"><img src="https://img.shields.io/github/release/r-spacex/SpaceX-API.svg?style=flat-square"></a>
-<a href="https://en.wikipedia.org/wiki/Representational_state_transfer"><img src="https://img.shields.io/badge/interface-REST-brightgreen.svg?style=flat-square"></a>
+<a href="https://travis-ci.org/r-spacex/SpaceX-API"><img src="https://img.shields.io/travis/r-spacex/SpaceX-API.svg?longCache=true&style=for-the-badge"></a>
+<a href="https://hub.docker.com/r/jakewmeyer/spacex-api/"><img src="https://img.shields.io/docker/build/jakewmeyer/spacex-api.svg?longCache=true&style=for-the-badge"></a>
+<a href="https://github.com/r-spacex/SpaceX-API/releases"><img src="https://img.shields.io/github/release/r-spacex/SpaceX-API.svg?longCache=true&style=for-the-badge"></a>
+<a href="https://en.wikipedia.org/wiki/Representational_state_transfer"><img src="https://img.shields.io/badge/interface-REST-brightgreen.svg?longCache=true&style=for-the-badge"></a>
 </p>
 
 <h3 align="center">Open Source REST API for rocket, core, capsule, pad, and launch data</h3>