chore(deps): update base64 requirement from 0.22 to 0.23 (#1059)

Updates the requirements on [base64](https://github.com/marshallpierce/rust-base64) to permit the latest version.
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](https://github.com/marshallpierce/rust-base64/compare/v0.22.0...v0.23.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-version: 0.23.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

crates/rmcp/Cargo.toml

@@ -64,7 +64,7 @@ jsonwebtoken = { version = "11", optional = true, features = ["aws_lc_rs"] }
 schemars = { version = "1.0", optional = true, features = ["chrono04"] }
 
 # for image encoding
-base64 = { version = "0.22", optional = true }
+base64 = { version = "0.23", optional = true }
 
 # for SEP-2322 requestState integrity sealing (opt-in via the `request-state` feature)
 hmac = { version = "0.13", optional = true }