[docs] pkg-config missing in build-dependency docs in README.md

[Zugschlus]

Hi,

when trying to build vzlogger on Debian stable in a clean container, after installing the packages explicitly recommended in the README.md, the cmake process fails because it cannot find the GnuTLS libraries, despite them being there. This was ultimately caused by pkg-config missing in the container.

The README.md file should recommend pkg-config additionally for building on Debian-flavored OSses. pkg-config is there in the recommended list for Debian wheezy, but is missing in all other distribution stanzas.

Btw, on buster and more current Debian OSses, a user can 'apt build-dep ./' to install the Build-Dependencies listed in debian/control even when not actually using the Debian package code. Using this can probably save you a bit of documentation work and will also help to keep debian/control current.

Greetings Marc

[r00t-]

thanks for the report. would you mind just creating an MR that updates the README? appears easier than somebody else implementing according to your description. (and can be done conveniently from the gitlab web ui, if no local working copy is at hand: https://github.com/volkszaehler/vzlogger/edit/master/README.md )