Fix deprecations

Author: ajohnson6494

.github/workflows/main.yml

@@ -6,7 +6,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
-        php-versions: ['8.3', '8.2']
+        php-versions: ['8.4', '8.3']
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v1

.phpunit.cache/test-results

@@ -0,0 +1 @@
+{"version":1,"defects":[],"times":{"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body":0.015,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_attachment":0.003,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_given_css":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_given_css_and_attachment":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_and_text_parts":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_and_text_parts_with_attachment":0.001,"Tests\\CssInlinerPluginTest::test_it_should_leave_plain_text_unmodified":0,"Tests\\CssInlinerPluginTest::test_it_should_leave_plain_text_unmodified_with_attachment":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_as_a_part":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_as_a_part_with_attachment":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_link_css":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_link_css_and_attachment":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_links_css":0.001,"Tests\\CssInlinerPluginTest::test_it_should_convert_html_body_with_links_css_and_attachment":0.001}}

src/CssInlinerPlugin.php

@@ -19,7 +19,7 @@ class CssInlinerPlugin
 
     private string $cssToAlwaysInclude;
 
-    public function __construct(array $filesToInline = [], CssToInlineStyles $converter = null)
+    public function __construct(array $filesToInline = [], ?CssToInlineStyles $converter = null)
     {
         $this->cssToAlwaysInclude = $this->loadCssFromFiles($filesToInline);
 

tests/CssInlinerPluginTest.php

@@ -342,7 +342,7 @@ private function fakeSendMessageUsingInlinePlugin(Email $message, array $inlineC
         return $processedMessage;
     }
 
-    private function createMessageToSend(Email $message, string $attachmentPath = null): Email
+    private function createMessageToSend(Email $message, ?string $attachmentPath = null): Email
     {
         $message = $message->to('[email protected]')
                     ->from('[email protected]')