Set hello world question to difficulty 0 for tutorial difficulty

Author: TianLangHin

competition/01-hello/prob.md

@@ -24,7 +24,7 @@ exec = ["deno", "run", "-qA", "judge.ts"]
 
 [problem]
 points = 1
-difficulty = 1
+difficulty = 0
 ---
 
 # 👋 Hello Programmers!