fix(MainComponent.cpp): Fixed segmentation fault on unsuccessful version request

[mfep]

• decomposeURL in the Linux JUCE backend cannot handle anything other than HTTP, see here
• The above caused a nullptr dereference in the version check routine, at least on Linux on every startup
  • The proper solution of course would be to implement HTTPS. According to the documentation, JUCE doesn't support this out of the box.
  • I'm sure that many cross-platform 3rd party options exist for that, but it is also not difficult to roll your own using platform specific dependencies. E.g. I did the latter in my own project: Windows, Linux
• I've added a check to avoid dereferencing the nullptr
• I think that this fixes #29
• Thank you for creating this, keep it up! :heart:

[dan-german]

thanks a bunch for this! linux users are going to be happy! feel free joining our discord channel if you're not there yet :)