Bump log4j-core in /python/rpdk/java/templates/init/shared (#381)

Bumps log4j-core from 2.13.3 to 2.15.0.

---
updated-dependencies:
- dependency-name: org.apache.logging.log4j:log4j-core
  dependency-type: direct:production
...

Author: dependabot[bot]

python/rpdk/java/templates/init/shared/pom.xml

@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.apache.logging.log4j</groupId>
             <artifactId>log4j-core</artifactId>
-            <version>2.13.3</version>
+            <version>2.15.0</version>
         </dependency>
         <!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-slf4j-impl -->
         <dependency>