Linux Beta uploaded

We uploaded the Linux beta version of Lovely Composer. It's x86_64bit version, so Arm Linux and Raspberry Pi are not supported now.

We have only confirmed it on Ubuntu 20.04, but I would appreciate it if you could report the operation!

Linux version is made in AppImage format, so you must set execution permission to "lovely_composer.bin" by file properties or Terminal before run.

 (command)

   chmod u+x lovely_composer.bin

* The contents are almost the same as ver.1.2.3.