Update Changelog (Demo 1.3)

I'm currently working towards level 2, but in the meanwhile, i remade the entire first bossfight, and a few tweaks to the miniboss

Changes include

• New battle arena (1st boss)
• New boss patterns (1st boss)
• New chase sequence (1st boss)
• Nerfed attacks (1st Miniboss)
• Decorated the ending properly (last room before the credits)

The rest of the game is the same as before,