Fix SBSv2 SDK filtering. (1) When only SBSv2 is available, assume all SDKs are SBSv2-capable. (2) In the SBSv1+SBSv2 case, ensure the version check >= 8.3 is correct (it was disallowing anything with minor version < 3).

source.sourcegen.jar = src/
output.sourcegen.jar = bin/
bin.includes = plugin.xml,\
               sourcegen.jar,\
               icons/,\
               META-INF/