[CCDB-5300] Upgrade postgresql to 42.4.3

Problem

Vulnerable dependency "postgresql" for kafka-connect-jdbc CVE: https://confluentinc.atlassian.net/browse/CCDB-5300

Solution

Upgrade postgresql to 42.4.3 as per here.

Does this solution apply anywhere else?

[ ] yes
[x] no

If yes, where?

Test Strategy

mvn dependency:tree output

[INFO] +- org.xerial:sqlite-jdbc:jar:3.25.2:runtime
[INFO] +- org.postgresql:postgresql:jar:42.4.3:runtime
[INFO] |  \- org.checkerframework:checker-qual:jar:3.5.0:runtime
[INFO] +- com.oracle.database.jdbc:ojdbc8-production:pom:19.7.0.0:runtime
[INFO] |  +- com.oracle.database.jdbc:ojdbc8:jar:19.7.0.0:runtime

Testing done:

[ ] Unit tests
[ ] Integration tests
[ ] System tests
[ ] Manual tests

Release Plan

[CCDB-5300]: https://confluentinc.atlassian.net/browse/CCDB-5300?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

confluentinc / kafka-connect-jdbc

[CCDB-5300] Upgrade postgresql to 42.4.3 #1286