Migrating to PHPUnit 8

<!-- Before -->
<blacklist>
    <directory>./config</directory>
</blacklist>

<!-- After -->
<whitelist>
    <exclude>
        <directory>./config</directory>
    </exclude>
</whitelist>

// Before
use PHPUnit_Framework_TestCase;
use PHPUnit_Framework_MockObject_MockObject;
use PHPUnit_Framework_MockObject_Stub_ConsecutiveCalls;
use PHPUnit_Framework_MockObject_InvocationMocker;

// After
use PHPUnit\Framework\TestCase;
use PHPUnit\Framework\MockObject\MockObject;
use PHPUnit\Framework\MockObject\Stub\ConsecutiveCalls;
use PHPUnit\Framework\MockObject\InvocationMocker;
...etc

// Before
public function setUp()
public function tearDown()
public static function setUpBeforeClass()
public static function tearDownAfterClass()

// After
public function setUp(): void
public function tearDown(): void
public static function setUpBeforeClass(): void
public static function tearDownAfterClass(): void

// Before
$serviceMock = $this->getMock(
    'Service',
    array('update'),
    $params,
    '',
    false
);

// After
$serviceMock = $this->getMockBuilder('Service')
    ->setMethods(array('update'))
    ->setConstructorArgs($params)
    ->setMockClassName('')
    ->disableOriginalConstructor()
    ->getMock();
);

// Before
/**
 * Test that an exception is thrown when an unsupported form type is specified
 *
 * @expectedException InvalidArgumentException
 * @expectedExceptionMessage Invalid!
 */
public function testInstantiateContactFormThrowsException()
{
    (new ContactForm('foo'));
}

public function testInstantiateContactFormThrowsException()
{
    $this->setExpectedException('InvalidArgumentException', 'Invalid!');
    (new ContactForm('foo'));
}

// After
/**
 * Test that an exception is thrown when an unsupported form type is specified
 */
public function testInstantiateContactFormThrowsException()
{
    $this->expectException('InvalidArgumentException');
    $this->expectExceptionMessage('Invalid!');
    (new ContactForm('foo'));
}

// Before
$this->assertContains('needle', 'haystack');
$this->assertNotContains('needle', 'haystack');

// After
$this->assertStringContainsString('needle', 'haystack');
$this->assertStringNotContainsString('needle', 'haystack');

// Before
public function testDataProvider()
{
}

/**
 * @dataProvider testDataProvider
 */
public function testPayload()
{
}

// After
public function myDataProvider()
{
}

/**
 * @dataProvider myDataProvider
 */
public function testPayload()
{
}

// Before
$this->assertNull(null, $iAmNull);

// After
$this->assertNull($iAmNull);