drone: build version not getting set correctly

Created by: iameli

When I build Mist locally (via livepeer/catalyst), the CMake stuff takes care of populating the binary version:

MistController --version
Version: mist-v3.0-91-gd10947e, release Generic_64

The Drone builds don't seem to have this property:

MistController --version
Version: Unknown, release Generic_64
- Flag: Shared memory disabled. Will use shared files in stead of shared memory as IPC method.
Built on Jul 21 2022, 20:09:51

Gotta be something broken in the version tags in CMakeLists.txt?