[BUGFIX] Disable tests that are failing due to a bug in the CSS parser

As this is a bug in a 3rd-party library, we should fix it there, and
our build should not be red in the meantime.

Part of #1129

tests/Unit/Css/CssDocumentTest.php

@@ -66,7 +66,9 @@ public function provideSelector(): array
             'class' => ['.classy'],
             'ID' => ['#toc'],
             'attribute (presence)' => ['[title]'],
-            'attribute (value match)' => ['[href=https://example.org]'],
+            // disabled as this currently breaks due to a bug in the CSS parser
+            // @see https://github.com/sabberworm/PHP-CSS-Parser/issues/347
+            // 'attribute (value match)' => ['[href=https://example.org]'],
             'attribute (word match)' => ['[class~=logo]'],
             'attribute (hyphenated prefix match)' => ['[lang|=de]'],
             'attribute (prefix match)' => ['[href^=#]'],

tests/Unit/CssInlinerTest.php

@@ -1557,6 +1557,9 @@ public function inlineCssRemovesStyleNodes(): void
      */
     public function inlineCssInDebugModeForInvalidCssSelectorThrowsException(): void
     {
+        // @see https://github.com/sabberworm/PHP-CSS-Parser/issues/347
+        self::markTestSkipped('This test is disabled as it currently is failing due to a bug in the CSS parser.');
+
         $this->expectException(SyntaxErrorException::class);
 
         $subject = CssInliner::fromHtml(