v0.54.2

- Java: Handle absurd numbers of recipients in multi-recipient messages

- Java: Exclude native libraries from the "sources" artifacts uploaded
  to Maven

- Java: Special-case the arch-specific load to handle JREs that use
  "x86_64" instead of "amd64"

- Node: Don't force binary encoding for incremental MAC streams

- Further updates to the backup validator, including omitting the
  backup timestamp and sorting reactions in the canonical string

- Update to boring v4.9.0