Move the CI from Travis CI to GitHub Actions

Travis CI has dropped free support for open source projects.

To continue having CI builds, we now use GitHub Actions for this.

Author: oliverklee

.gitattributes

@@ -1,6 +1,6 @@
 /.gitattributes export-ignore
+/.github/ export-ignore
 /.gitignore export-ignore
-/.travis.yml export-ignore
 /Doxyfile export-ignore
 /phpunit.xml export-ignore
 /tests export-ignore

.github/workflows/ci.yml

@@ -0,0 +1,56 @@
+# https://help.github.com/en/categories/automating-your-workflow-with-github-actions
+
+on:
+  pull_request:
+  push:
+  schedule:
+    - cron: '3 3 * * 1'
+
+name: CI
+
+jobs:
+  unit-tests:
+    name: Unit tests
+
+    runs-on: ubuntu-20.04
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - 5.3
+          - 5.4
+          - 5.5
+          - 5.6
+          - 7.0
+          - 7.1
+          - 7.2
+          - 7.3
+          - 7.4
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          tools: composer:v2
+          coverage: none
+
+      - name: Cache dependencies installed with composer
+        uses: actions/cache@v1
+        with:
+          path: ~/.cache/composer
+          key: php${{ matrix.php-version }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            php${{ matrix.php-version }}-composer-
+
+      - name: Install Composer dependencies
+        run: |
+          composer update --with-dependencies --no-progress;
+          composer show;
+
+      - name: Run Tests
+        run: ./vendor/bin/phpunit

.travis.yml

@@ -1,7 +1,7 @@
 PHP CSS Parser
 --------------
 
-[![build status](https://api.travis-ci.org/sabberworm/PHP-CSS-Parser.svg)](https://travis-ci.org/sabberworm/PHP-CSS-Parser)
+[![Build Status](https://github.com/sabberworm/PHP-CSS-Parser/workflows/CI/badge.svg?branch=master)](https://github.com/sabberworm/PHP-CSS-Parser/actions/)
 
 A Parser for CSS Files written in PHP. Allows extraction of CSS files into a data structure, manipulation of said structure and output as (optimized) CSS.