Remove usage of deprecated utf8_encode function

utf8_encode is deprecated in PHP 8.2. Fortunately, we're already making
use of iconv, and it's straightforward enough to use iconv to convert
from ISO-8859-1 instead of utf8_encode.

src/Raygun4php/RaygunRequestMessage.php

@@ -42,7 +42,7 @@ public function __construct()
  $utf8_convert_server = function ($value) use (&$utf8_convert_server) {
  return is_array($value) ?
  array_map($utf8_convert_server, $value) :
- iconv('UTF-8', 'UTF-8', utf8_encode($value));
+ iconv('ISO-8859-1', 'UTF-8', $value);
  };
 
  $this->Form = array_map($utf8_convert, $_POST);

tests/RaygunClientTest.php

@@ -277,4 +277,19 @@ public function testValidateMessageJsonInTransportObj()
  $schemaValidator->validate($data, $this->jsonSchema);
  $this->assertTrue($schemaValidator->isValid());
  }
+
+ /**
+ * @backupGlobals enabled
+ */
+ public function testServerUtf8Conversion()
+ {
+ $_SERVER = [
+ 'a' => 'hello',
+ 'b' => "\xc0\xde",
+ ];
+ $requestMessage = new RaygunRequestMessage();
+
+ $this->assertSame('hello', $requestMessage->Data['a']);
+ $this->assertSame('ÀÞ', $requestMessage->Data['b']);
+ }
 }