fix: upgrade multiple dependencies with Snyk

Snyk has created this PR to upgrade:
  - com.sparkjava:spark-core from 2.7.2 to 2.9.4.
    See this package in maven: https://mvnrepository.com/artifact/com.sparkjava/spark-core/
  - org.slf4j:slf4j-simple from 1.7.21 to 1.7.36.
    See this package in maven: https://mvnrepository.com/artifact/org.slf4j/slf4j-simple/

See this project in Snyk:
https://app.snyk.io/org/nexuscompute/project/7f64f146-ad31-4b9e-aab4-bad54d56c39d?utm_source=github&utm_medium=referral&page=upgrade-pr

code-samples/serving/hello-world/helloworld-java-spark/pom.xml

@@ -46,13 +46,13 @@
 		<dependency>
 			<groupId>com.sparkjava</groupId>
 			<artifactId>spark-core</artifactId>
-			<version>2.7.2</version>
+			<version>2.9.4</version>
 		</dependency>
 		<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-simple</artifactId>
-			<version>1.7.21</version>
+			<version>1.7.36</version>
 		</dependency>
 
 	</dependencies>