Remove Travis CI

Travis CI changed their pricing model.  When I first heard about it, I
mistakenly thought that 10K credits equates to 10,000 builds, giving me
plenty of time to migrate to a different CI service.  I have since
learned that 10K credits is about 1,000 *minutes* of build time.  I am
already over halfway through those credits!  I am removing Travis CI and
hope to find time to configure a new CI service in the near future.

Author: TravisCardwell

.travis.yml

@@ -26,6 +26,10 @@ following conventions:
 
 ## Unreleased
 
+### Non-Breaking
+
+* Remove Travis CI
+
 ## 0.5.0.0 (2020-11-08)
 
 ### Breaking

CHANGELOG.md

@@ -1,7 +1,5 @@
 # Queue Sheet
 
-[![Build Status](https://travis-ci.com/ExtremaIS/queue-sheet-haskell.svg?branch=main)](https://travis-ci.com/ExtremaIS/queue-sheet-haskell)
-
 * [Overview](#overview)
 * [Requirements](#requirements)
 * [Installation](#installation)