Bump com.amazonaws.serverless:aws-serverless-java-container-spring

Bumps [com.amazonaws.serverless:aws-serverless-java-container-spring](https://github.com/aws/serverless-java-container) from 2.1.3 to 2.1.5.
- [Release notes](https://github.com/aws/serverless-java-container/releases)
- [Commits](aws/serverless-java-container@aws-serverless-java-container-2.1.3...aws-serverless-java-container-2.1.5)

---
updated-dependencies:
- dependency-name: com.amazonaws.serverless:aws-serverless-java-container-spring
  dependency-version: 2.1.5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

labs/unicorn-stock-broker/pom.xml

@@ -40,7 +40,7 @@
         <dependency>
             <groupId>com.amazonaws.serverless</groupId>
             <artifactId>aws-serverless-java-container-spring</artifactId>
-            <version>2.1.3</version>
+            <version>2.1.5</version>
         </dependency>
 
         <dependency>