Bump com.sap.cloud.db.jdbc:ngdbc from 2.17.10 to 2.21.11

Bumps com.sap.cloud.db.jdbc:ngdbc from 2.17.10 to 2.21.11.

---
updated-dependencies:
- dependency-name: com.sap.cloud.db.jdbc:ngdbc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/pom.xml

@@ -387,7 +387,7 @@
         <dependency>
             <groupId>com.sap.cloud.db.jdbc</groupId>
             <artifactId>ngdbc</artifactId>
-            <version>2.17.10</version>
+            <version>2.21.11</version>
         </dependency>
         <dependency>
             <groupId>io.prometheus</groupId>