meson: set soversion

[jbicha]

This sets up the symlinked shared library as expected.

[hellsworth]

Also @mjakeman could make sure to bump the soname if you make API-incompatible changes :)

[mjakeman]

Thanks!

Just a heads up: I'm planning to relicense this project one more (final, I promise) time to dual MPL-2.0/LGPL-2.1-or-later for license compatibility with GTK and permissive static linking. As a formality - can you confirm you are happy to commit under this license?

Also mjakeman could make sure to bump the soname if you make API-incompatible changes :)

Will do 👍

[jbicha]

Just a heads up: I'm planning to relicense this project one more (final, I promise) time to dual MPL-2.0/LGPL-2.1-or-later for license compatibility with GTK and permissive static linking. As a formality - can you confirm you are happy to commit under this license?

Yes, you are free to relicense this commit under those licenses.