Bump postgresql from 42.2.20 to 42.2.21 (#7817)

Bumps [postgresql](https://github.com/pgjdbc/pgjdbc) from 42.2.20 to 42.2.21.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/REL42.2.21/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.2.20...REL42.2.21)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -153,7 +153,7 @@ dependencies {
 
     implementation group: 'org.mariadb.jdbc', name: 'mariadb-java-client', version: '2.7.3'
 
-    implementation 'org.postgresql:postgresql:42.2.20'
+    implementation 'org.postgresql:postgresql:42.2.21'
 
     implementation ('com.oracle.ojdbc:ojdbc10:19.3.0.0') {
         // causing module issues