[SPARK-50894][SQL] Postgres driver version bump to 42.7.5

### What changes were proposed in this pull request?

In this PR, I propose upgrading the version of `PostgreSQL` driver version to `42.7.5`. More specifically, in this [PR](#47810), the following regression was introduced:
`Postgres` driver was not compatible for connection to the `Redshift` Data Source. This happened because the `42.7.4` driver version unnecessarily sent `SET extra_float_digits = 3` queries to the destination data source when establishing the connection. However, the upper limit for `extra_float_digits` parameter in `Redshift` is 2.

Regarding the release notes of version [42.7.5](https://github.com/pgjdbc/pgjdbc/releases/tag/REL42.7.5), I propose to upgrade the version of the driver, because the behavior of sending queries which set `extra_flow_digits` when establishing connection was fixed in this version.

### Why are the changes needed?

This changes are essential when trying to properly connect to the Redshift instance from OSS.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

N/A.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #49575 from vladanvasi-db/vladanvasi-db/postrgesql-driver-fix.

Authored-by: Vladan Vasić <[email protected]>
Signed-off-by: Wenchen Fan <[email protected]>

Author: vladanvasi-db

pom.xml

@@ -330,7 +330,7 @@
     </extraJavaTestArgs>
     <mariadb.java.client.version>2.7.12</mariadb.java.client.version>
     <mysql.connector.version>9.1.0</mysql.connector.version>
-    <postgresql.version>42.7.4</postgresql.version>
+    <postgresql.version>42.7.5</postgresql.version>
     <db2.jcc.version>11.5.9.0</db2.jcc.version>
     <mssql.jdbc.version>12.8.1.jre11</mssql.jdbc.version>
     <ojdbc17.version>23.6.0.24.10</ojdbc17.version>