Bump nostr-sdk from 0.27.0 to 0.30.0

Bumps [nostr-sdk](https://github.com/rust-nostr/nostr) from 0.27.0 to 0.30.0.
- [Release notes](https://github.com/rust-nostr/nostr/releases)
- [Changelog](https://github.com/rust-nostr/nostr/blob/master/CHANGELOG.md)
- [Commits](rust-nostr/nostr@v0.27.0...v0.30.0)

---
updated-dependencies:
- dependency-name: nostr-sdk
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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