[maven-release-plugin] prepare release RoaringBitmap-0.5.15
[maven-release-plugin] prepare release RoaringBitmap-0.5.15

gssiyankai/RoaringBitmap,lemire/RoaringBitmap,lemire/RoaringBitmap,okrische/RoaringBitmap,gssiyankai/RoaringBitmap,RoaringBitmap/RoaringBitmap,okrische/RoaringBitmap,lemire/RoaringBitmap,RoaringBitmap/RoaringBitmap,RoaringBitmap/RoaringBitmap,okrische/RoaringBitmap,gssiyankai/RoaringBitmap,lemire/RoaringBitmap,RoaringBitmap/RoaringBitmap