package/kodi-pvr-hts: bump version to 8.2.1-Matrix

package/kodi-pvr-hts: bump version to 8.2.1-Matrix

Switch dependency to kodi after upstream removed the dependency to
kodi-platform:
https://github.com/kodi-pvr/pvr.hts/commit/9943d05ce52b6ddcd63a3faa094f7ee9b2671c86
https://github.com/kodi-pvr/pvr.hts/commit/d6b71de38b1c522a6f2716a7e4a90528ae06e992

Added dependency to gcc >= 7 due to c++17 code added by
https://github.com/kodi-pvr/pvr.hts/commit/954f25d39652098b5fb1a55d44e2d410de78902b

Switch license file to LICENSE.md.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>