pkg/relic: check for minimal cmake version
pkg/relic: check for minimal cmake version

relic does not build with cmake < 3.6.0. This checks for a minimal version
instead of failing to compile.

    cmake version 3.5.2 is not >= to minimal required 3.6.0

    Makefile:25: recipe for target '..cmake_version_supported' failed

smlng/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,authmillenon/RIOT,rfuentess/RIOT,toonst/RIOT,basilfx/RIOT,OTAkeys/RIOT,mfrey/RIOT,jasonatran/RIOT,gebart/RIOT,cladmi/RIOT,A-Paul/RIOT,OlegHahm/RIOT,cladmi/RIOT,BytesGalore/RIOT,gebart/RIOT,jasonatran/RIOT,yogo1212/RIOT,BytesGalore/RIOT,mfrey/RIOT,mtausig/RIOT,avmelnikoff/RIOT,OlegHahm/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,miri64/RIOT,mtausig/RIOT,OlegHahm/RIOT,josephnoir/RIOT,basilfx/RIOT,OlegHahm/RIOT,ant9000/RIOT,lazytech-org/RIOT,ant9000/RIOT,A-Paul/RIOT,jasonatran/RIOT,authmillenon/RIOT,josephnoir/RIOT,rfuentess/RIOT,authmillenon/RIOT,rfuentess/RIOT,mfrey/RIOT,mfrey/RIOT,yogo1212/RIOT,kaspar030/RIOT,biboc/RIOT,kbumsik/RIOT,lazytech-org/RIOT,smlng/RIOT,BytesGalore/RIOT,rfuentess/RIOT,kbumsik/RIOT,mtausig/RIOT,yogo1212/RIOT,yogo1212/RIOT,kaspar030/RIOT,x3ro/RIOT,aeneby/RIOT,biboc/RIOT,yogo1212/RIOT,gebart/RIOT,authmillenon/RIOT,x3ro/RIOT,kaspar030/RIOT,jasonatran/RIOT,smlng/RIOT,OlegHahm/RIOT,A-Paul/RIOT,aeneby/RIOT,avmelnikoff/RIOT,BytesGalore/RIOT,miri64/RIOT,cladmi/RIOT,x3ro/RIOT,toonst/RIOT,lazytech-org/RIOT,smlng/RIOT,kYc0o/RIOT,kaspar030/RIOT,mtausig/RIOT,avmelnikoff/RIOT,aeneby/RIOT,toonst/RIOT,OTAkeys/RIOT,ant9000/RIOT,josephnoir/RIOT,gebart/RIOT,miri64/RIOT,rfuentess/RIOT,basilfx/RIOT,smlng/RIOT,miri64/RIOT,OTAkeys/RIOT,biboc/RIOT,aeneby/RIOT,gebart/RIOT,avmelnikoff/RIOT,cladmi/RIOT,kYc0o/RIOT,lazytech-org/RIOT,RIOT-OS/RIOT,biboc/RIOT,kbumsik/RIOT,kbumsik/RIOT,x3ro/RIOT,mtausig/RIOT,A-Paul/RIOT,aeneby/RIOT,RIOT-OS/RIOT,basilfx/RIOT,kaspar030/RIOT,josephnoir/RIOT,ant9000/RIOT,A-Paul/RIOT,authmillenon/RIOT,authmillenon/RIOT,kYc0o/RIOT,OTAkeys/RIOT,cladmi/RIOT,lazytech-org/RIOT,kYc0o/RIOT,toonst/RIOT,miri64/RIOT,kYc0o/RIOT,yogo1212/RIOT,biboc/RIOT,josephnoir/RIOT,BytesGalore/RIOT,basilfx/RIOT,toonst/RIOT,kbumsik/RIOT,avmelnikoff/RIOT,x3ro/RIOT,mfrey/RIOT,ant9000/RIOT,OTAkeys/RIOT