doc: Update supported A2DP version to 1.3
doc: Update supported A2DP version to 1.3

pkarasev3/bluez,mapfau/bluez,silent-snowman/bluez,ComputeCycles/bluez,ComputeCycles/bluez,silent-snowman/bluez,pkarasev3/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,silent-snowman/bluez,ComputeCycles/bluez,mapfau/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,silent-snowman/bluez,mapfau/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez