Added audio files and credits file

Author: Callum-OP

assets/Credits

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+Credits
+
+Audio:
+- GoldPickup (money-pickup-2) and HealthPickup (coin_2) by freesound_community (Pixabay.com)
+    Free for commercial use
+    Licensed under Pixabay Content License: https://pixabay.com/service/license/
+
+Images:
+- any images used are my own creation (Callum O'Prey)
+
+Fonts:
+- MagicSchoolOne by Michael Hagemann (FontMesa)
+    Free for commercial use
+    Source: https://www.1001fonts.com/magic-school-font.html
+
+- Dumbledor (dum1) by GemFonts / Typotheticals
+    Free for commercial use
+    Source: https://www.dafont.com/dumbledor.font
+