fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTY-5902998
- https://snyk.io/vuln/SNYK-JAVA-ORGJETBRAINSKOTLIN-2393744
- https://snyk.io/vuln/SNYK-JAVA-ORGJETBRAINSKOTLIN-2628385

pom.xml

@@ -17,7 +17,7 @@
         <maven.compiler.plugin>2.4</maven.compiler.plugin>
         <maven.shade.plugin>3.1.0</maven.shade.plugin>
         <dockerfile.maven.plugin>1.2.2</dockerfile.maven.plugin>
-        <javalin.version>4.5.0</javalin.version>
+        <javalin.version>4.6.4</javalin.version>
         <mockito.version>3.7.7</mockito.version>
         <junit.version>5.7.1</junit.version>
         <konghg.unirest>3.4.00</konghg.unirest>