feat: Add Polish translations (#375)

Author: maciejkrol18

src/translations.php

@@ -135,6 +135,14 @@
         "Longest Streak" => "Langste Serie",
         "Present" => "Vandaag",
     ],
+    "pl" => [
+        "Total Contributions" => "Suma Kontrybucji",
+        "Current Streak" => "Aktualna Seria",
+        "Longest Streak" => "Najdłuższa Seria",
+        "Week Streak" => "Seria Tygodni",
+        "Longest Week Streak" => "Najdłuższa Seria Tygodni",
+        "Present" => "Dziś",
+    ],
     "pt-br" => [
         "Total Contributions" => "Total de Contribuições",
         "Current Streak" => "Atual Sequência",