zig 0.14.0-dev.1421+f87dd43c1 update + repeated message fix + more tests

[GrownNed]

Updated the implementation to zig version 0.14.0.

• Fixed a bug when deserializing repeated message fields (previously, the decodeSingleScalar function was mistakenly used instead of decodeSingleValue when reading repeated fields, which made it impossible to deserialize sub-messages).
• Allowed default values for strings and byte arrays.
• Fixed .repeat_pack encoding (skip encoding if the list is empty).

Public API change:

• decodeMessage -> decode
• encodeMessage -> encode

Parameters in those functions were sorted in the order they appear in functions from std.
Additionally, a couple of new tests were written.