CI: update repository URL for love-appimage-source

.github/workflows/main.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Checkout love-appimage-source
       uses: actions/checkout@v2
       with:
-        repository: MikuAuahDark/love-appimage-source
+        repository: love2d/love-appimage-source
     - name: Checkout LÖVE
       uses: actions/checkout@v2
       with: