CI: migrate from Travis CI to Github Actions

- Removed .travis.yml and shellcheck.sh
- Added CI badge to README

.travis.yml

@@ -1,12 +0,0 @@
-sudo: required
-dist: trusty
-
-before_install:
-  - echo 'deb http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse' | sudo tee -a /etc/apt/sources.list
-  - sudo apt-get -qq update
-  - sudo apt-get install -y shellcheck
-
-git:
-  depth: 3
-
-script: ./shellcheck.sh

readme.md

@@ -1,5 +1,7 @@
 # Improved Nano Syntax Highlighting Files
 
+[![shellcheck](https://github.com/davidhcefx/nanorc/actions/workflows/shellcheck.yml/badge.svg?branch=master)](https://github.com/davidhcefx/nanorc/actions/workflows/shellcheck.yml)
+
 This repository holds ``{lang}.nanorc`` files that have improved definitions of syntax highlighting for various languages.
 
 ## Installation

shellcheck.sh

@@ -1,4 +0,0 @@
-#!/bin/sh -ev
-# Shellcheck the script
-
-shellcheck install.sh