Merge pull request #1343 from 52North/dependabot/maven/version.springframework-5.3.21

Bump version.springframework from 5.3.20 to 5.3.21

Author: CarstenHollmann

pom.xml

@@ -87,7 +87,7 @@
         <version.helgoland.api>3.4.2</version.helgoland.api>
         <version.dao-impl>3.5.2</version.dao-impl>
         <version.db-model>3.2.0-SNAPSHOT</version.db-model>
-        <version.springframework>5.3.20</version.springframework>
+        <version.springframework>5.3.21</version.springframework>
         <version.springframework.security>5.7.1</version.springframework.security>
         <version.aspectj>1.9.9.1</version.aspectj>
         <version.saxon>11.3</version.saxon>