Bump postgresql from 42.3.1 to 42.3.2 in /backend

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.3.1 to 42.3.2.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.3.1...REL42.3.2)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-type: direct:production
...

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

backend/pom.xml

@@ -18,7 +18,7 @@
         <jjwt.version>0.11.2</jjwt.version>
         <jackson.kotlin.module.version>2.13.1</jackson.kotlin.module.version>
         <flyway.version>8.4.3</flyway.version>
-        <postgresql.driver.version>42.3.1</postgresql.driver.version>
+        <postgresql.driver.version>42.3.2</postgresql.driver.version>
         <bouncycastle.version>1.70</bouncycastle.version>
 
         <!-- Maven plugin version -->