fix(deps): update spring core to v5.3.21

Author: renovate[bot]

pom.xml

@@ -29,7 +29,7 @@
         <jackson.version>2.13.3</jackson.version>
         <jersey.version>2.35</jersey.version>
         <jetty.version>9.4.47.v20220610</jetty.version>
-        <spring.version>5.3.20</spring.version>
+        <spring.version>5.3.21</spring.version>
         <slf4j.version>1.7.36</slf4j.version>
         <hystrix.version>1.5.18</hystrix.version>
         <maven.javadoc.skip>true</maven.javadoc.skip>