fix: samples/client/petstore/java/restclient-swagger2/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-10345766
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230364
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230365
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-7687447
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-10176071
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230366

Author: snyk-bot

samples/client/petstore/java/restclient-swagger2/pom.xml

@@ -280,7 +280,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <swagger-annotations-version>2.2.15</swagger-annotations-version>
-        <spring-web-version>6.1.6</spring-web-version>
+        <spring-web-version>6.1.21</spring-web-version>
         <jackson-version>2.17.1</jackson-version>
         <jackson-databind-version>2.17.1</jackson-databind-version>
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>