feat: add option to install a specific EspoCRM version

[aberonni]

closes #6

I've tested this with a new installation and it works as expected.

If you'd like to test, you can use the code from our fork like so:

wget https://raw.githubusercontent.com/rodekruis/espocrm-installer/refs/heads/master/install.sh
chmod +x install.sh # only necessary because of how we are downloading the file differently and not via a release - would not be necessary normally
sudo bash install.sh --version=8.4.2 # you can add any of the other command line parameters here

I think this is a nice addition, and valuable for the community, but I am also very open to feedback and adjustments if needed.

[oussama-saoudi]

Did you test this script with -ssl flag?

[aberonni]

@oussama-saoudi no, this adds a new parameter, it shouldn't (in theory) affect or change the behaviour of existing parameters. Are you asking because of issues?

[oussama-saoudi]

Yes, the SSL LetsEncrypt installation part is not working on the one I'm using, maybe you can give it a try on your side.