Release instructions to README.

Standardized error messages as close to English rules as possible.

Changed several CriticalTrust APIs to be async.

Added a criticalup verify command that can be used to verify that a locally installed toolchain is not corrupted or tampered with.

Added criticalup archive which creates an archive of the toolchain for cold storage or backup.

Bug when using --offline mode to install with expired revocation info ends in installation failure. To support proper --offline mode, the expiration date on revocation info hash must be ignored.

Support for package revocation added, criticalup install will verify packages have not been revoked (due to, for example, a security event) before installation.

An --offline flag has been added to criticalup install, when enabled only the download cache will be used where possible, and the cache will not be populated on cache miss.

Caching of downloaded keys, manifests, and installation tarballs has been added. Newly downloaded artifacts will also be stored in the OS-specific cache directory. The cache can be cleaned with criticalup clean or any relevant OS behaviors.

tracing support was added for structured and multi-level logging. --verbose and -v are now generally accepted and enable debug logging. Passing the flag twice (eg. -vv) will enable trace logging as well. The --log-level argument can accept arbitrary tracing directives for fine grained control over logging where required.

Moved criticalup to an async runtime (tokio), this resulted in resolving some intermittent networking issues on low bandwidth or unreliable connections.

Retry downloads in case of network issue (#28).

Versioning issue where --version was still showing 0.0.0 (#24).

Update dependencies for all crates in the project workspace (#10).

Initial public release (#22).