apt-key is deprecated warning message while installing from script

Due to line 144, a warning will display regarding apt-key being deprecated.

Proposed fix:

Have the script create the following directory: /usr/share/keyrings
Change the curl statement that downloads the key to download the key to a local file, such as /usr/share/keyrings/pimox.gpg
Change the repository URL to become: deb [signed-by=/usr/share/keyrings/pimox.gpg] https://raw.githubusercontent.com/pimox/pimox7/master/ dev/

I will work on a pull request for this issue.

pimox / pimox7