Git should not be required in the master CMakeLists.txt

[abdes]

Currently it is required when updating the project's git revision hash. However, the GetGitRevisionDescription module already looks for Git and falls back as needed.

# ------------------------------------------------------------------------------
# Project description and (meta) information
# ------------------------------------------------------------------------------

# Get git revision
find_package(Git REQUIRED)
include(GetGitRevisionDescription)

The find_package(Git REQUIRED) should just be removed.