remove duplicate licenses also in Scancode2AlienSPDX

Signed-off-by: Alberto Pianon <alberto@pianon.eu>

aliens4friends/commons/scancode2alienspdx.py

@@ -72,6 +72,7 @@ class Scancode2AlienSPDX:
 				f.licenses_in_file = Scancode2AlienSPDX.remove_non_spdx_lics(
 					f.licenses_in_file
 				)
+			f.licenses_in_file = list(set(f.licenses_in_file))
 		self.set_package_and_document_metadata()
 
 	@staticmethod