Bump org.apache.shiro:shiro-core from 2.0.2 to 2.0.6

Bumps [org.apache.shiro:shiro-core](https://github.com/apache/shiro) from 2.0.2 to 2.0.6.
- [Release notes](https://github.com/apache/shiro/releases)
- [Changelog](https://github.com/apache/shiro/blob/main/RELEASE-NOTES)
- [Commits](apache/shiro@shiro-root-2.0.2...shiro-root-2.0.6)

---
updated-dependencies:
- dependency-name: org.apache.shiro:shiro-core
  dependency-version: 2.0.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/pom.xml

@@ -220,7 +220,7 @@
         <dependency>
             <groupId>org.apache.shiro</groupId>
             <artifactId>shiro-core</artifactId>
-            <version>2.0.2</version>
+            <version>2.0.6</version>
             <exclusions>
                 <!-- All these transitive deps are already bundled in shiro core-->
                 <exclusion>