bump dependencies (#3089)

src/Utils/HtmlToPdfConverter.php

@@ -12,10 +12,13 @@ namespace App\Utils;
 interface HtmlToPdfConverter
 {
     /**
-     * Returns the binary content of the PDF, which can be saved as file or send via Reponse.
+     * Returns the binary content of the PDF, which can be saved as file.
+     * Throws an exception if conversion fails.
+     *
      * @param string $html
      * @param array $options
-     * @return mixed
+     * @return string
+     * @throws \Exception
      */
-    public function convertToPdf(string $html, array $options = []);
+    public function convertToPdf(string $html, array $options = []): string;
 }

src/Utils/MPdfConverter.php

@@ -56,10 +56,10 @@ class MPdfConverter implements HtmlToPdfConverter
     /**
      * @param string $html
      * @param array $options
-     * @return mixed|string
+     * @return string
      * @throws \Mpdf\MpdfException
      */
-    public function convertToPdf(string $html, array $options = [])
+    public function convertToPdf(string $html, array $options = []): string
     {
         $options = array_merge(
             $this->sanitizeOptions($options),