Bump serde_with from 3.14.0 to 3.15.0

Bumps [serde_with](https://github.com/jonasbb/serde_with) from 3.14.0 to 3.15.0.
- [Release notes](https://github.com/jonasbb/serde_with/releases)
- [Commits](jonasbb/serde_with@v3.14.0...v3.15.0)

---
updated-dependencies:
- dependency-name: serde_with
  dependency-version: 3.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.lock

@@ -15,7 +15,7 @@ borsh = "^0.10"
 num-derive = "0.4"
 num-traits = "^0.2"
 serde = { version = "^1.0", features = ["derive"], optional = true }
-serde_with = { version = "^3.0", optional = true }
+serde_with = { version = "^3.15", optional = true }
 solana-program = "^2"
 thiserror = "^2.0"