phpunit: Don't fail on deprecation

Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Require ext-bcmath in composer.json and updated dependencies

Removed print_r() statement from test

Updated README and CHANGELOG

Added some more tests to TransferTest and some small updates to README

Updated CHANGELOG.md for v0.6

Use the LoggerAwareTrait in ClientBuilder

Updated CHANGELOG

Changed wallet Response classes according to the current wallet_rpc_s…

…erver_commands_defs.h definitions from the main Monero repo

Also removed "Alias: *None*." from the comments for the wallet classes