csolution.yml inclusion in this repository

[ken-mu]

Please consider including csolution.yml in this repository.

We use Keil Studio Cloud (KSC) and evaluate AVH.
But KSC update the .cprj schema version automatically and this update is not controllable.
We need to create the .cprj file from csolution.yml with csolution command again to update the new .cprj file with the new schema version (Currently 2.0.0 is the latest).

We think you've maintain csolution.yml because we can see demo.VHT_MPS3_Corstone_SSE-300.cprj is created from csolution 0.9.5.