chore(deps): update soroban-sdk requirement in /contracts

Updates the requirements on [soroban-sdk](https://github.com/stellar/rs-soroban-sdk) to permit the latest version.
- [Release notes](https://github.com/stellar/rs-soroban-sdk/releases)
- [Commits](stellar/rs-soroban-sdk@v26.0.1...v27.0.3)

---
updated-dependencies:
- dependency-name: soroban-sdk
  dependency-version: 27.0.3
  dependency-type: direct:production
...

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

Author: dependabot[bot]

contracts/Cargo.toml

@@ -4,10 +4,10 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
-soroban-sdk = "26.0.1"
+soroban-sdk = "27.0.3"
 
 [dev-dependencies]
-soroban-sdk = { version = "26.0.1", features = ["testutils"] }
+soroban-sdk = { version = "27.0.3", features = ["testutils"] }
 
 [features]
 testutils = ["soroban-sdk/testutils"]