fix: converter-codegen-testapp/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8384234

converter-codegen-testapp/pom.xml

@@ -21,7 +21,7 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
-            <version>2.6.6</version>
+            <version>3.0.0</version>
             <scope>provided</scope>
         </dependency>
         <dependency>