Release 7.0.0 (NNCP)

Minimal required Go version is 1.13.
Merkle Tree-based Hashing with BLAKE3 (MTH) is used instead of BLAKE2b. Because of that, there are backward incompatible changes of encrypted files (everything laying in the spool directory) and .meta files of chunked transfer.
Current implementation is far from being optimal: it lacks parallelizable calculations and has higher memory consumption: nearly 512 KiB for each 1 GiB of file’s data. Future performance and memory size optimizations should not lead to packet’s format change. But it is still several times faster than BLAKE2b.
Resumed online downloads, because of MTH, require reading only of the preceding part of file, not the whole one as was before.
nncp-hash utility appeared for calculating file’s MTH hash.
BLAKE2 KDF and XOF functions are replaced with BLAKE3 in encrypted packets. Lowering number of used primitives. Also, its encrypted packet’s header is used as an associated data during encryption.
MultiCast Discovery uses ff02::4e4e:4350 address instead of ff02::1.
nncp-cfgenc mistakenly asked passphrase three times during encryption.
nncp-stat reports about partly downloaded packets.
Updated dependencies.