Change Pyo3 version in Cargo dependency

Author: Fahad Zubair

codegen-server/python/src/main/kotlin/software/amazon/smithy/rust/codegen/server/python/smithy/PythonServerCargoDependency.kt

@@ -15,9 +15,9 @@ import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
  * For a dependency that is used in the client, or in both the client and the server, use [CargoDependency] directly.
  */
 object PythonServerCargoDependency {
-    val PyO3: CargoDependency = CargoDependency("pyo3", CratesIo("0.18"))
+    val PyO3: CargoDependency = CargoDependency("pyo3", CratesIo("0.20"))
     val PyO3Asyncio: CargoDependency =
-        CargoDependency("pyo3-asyncio", CratesIo("0.18"), features = setOf("attributes", "tokio-runtime"))
+        CargoDependency("pyo3-asyncio", CratesIo("0.20"), features = setOf("attributes", "tokio-runtime"))
     val Tokio: CargoDependency = CargoDependency("tokio", CratesIo("1.20.1"), features = setOf("full"))
     val TokioStream: CargoDependency = CargoDependency("tokio-stream", CratesIo("0.1.12"))
     val Tracing: CargoDependency = CargoDependency("tracing", CratesIo("0.1"))