Configure PHPUnit coverage reporting and add Coveralls badge to README

Author: joelbladt

README.md

@@ -2,6 +2,7 @@
 
 <p align="center">
 <a href="https://github.com/laravel/framework/actions"><img src="https://github.com/laravel/framework/workflows/tests/badge.svg" alt="Build Status"></a>
+<a href="https://coveralls.io/github/laravel/framework"><img src="https://coveralls.io/repos/github/laravel/framework/badge.svg" alt="Coverage Status" /></a>
 <a href="https://packagist.org/packages/laravel/framework"><img src="https://img.shields.io/packagist/dt/laravel/framework" alt="Total Downloads"></a>
 <a href="https://packagist.org/packages/laravel/framework"><img src="https://img.shields.io/packagist/v/laravel/framework" alt="Latest Stable Version"></a>
 <a href="https://packagist.org/packages/laravel/framework"><img src="https://img.shields.io/packagist/l/laravel/framework" alt="License"></a>

phpunit.xml.dist

@@ -7,11 +7,21 @@
          stopOnFailure="false"
          cacheDirectory=".phpunit.cache"
          backupStaticProperties="false">
+    <coverage>
+        <report>
+            <clover outputFile="build/logs/clover.xml"/>
+        </report>
+    </coverage>
     <testsuites>
         <testsuite name="Laravel Test Suite">
             <directory suffix="Test.php">./tests</directory>
         </testsuite>
     </testsuites>
+    <source>
+        <include>
+            <directory>src</directory>
+        </include>
+    </source>
     <php>
         <ini name="date.timezone" value="UTC" />
         <ini name="intl.default_locale" value="C.UTF-8" />