Upgrade to Coroutines 1.5.0

This commit upgrades to Coroutines 1.5.0 while retaining
Coroutines 1.4.x compatibility.

Closes gh-26897

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -878,7 +878,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 			return ReactiveFlowKt.asFlow(publisher);
 		}
 
-		@SuppressWarnings("unchecked")
+		@SuppressWarnings({"unchecked", "deprecation"})
 		@Nullable
 		private static Object awaitSingleOrNull(Publisher<?> publisher, Object continuation) {
 			return AwaitKt.awaitSingleOrNull(publisher, (Continuation<Object>) continuation);