deps: update dependency org.postgresql:postgresql to v42.7.8 (#2221)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [org.postgresql:postgresql](https://jdbc.postgresql.org) ([source](https://redirect.github.com/pgjdbc/pgjdbc)) | `42.7.7` -> `42.7.8` | [![age](https://developer.mend.io/api/mc/badges/age/maven/org.postgresql:postgresql/42.7.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/maven/org.postgresql:postgresql/42.7.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/maven/org.postgresql:postgresql/42.7.7/42.7.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/maven/org.postgresql:postgresql/42.7.7/42.7.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>pgjdbc/pgjdbc (org.postgresql:postgresql)</summary>

### [`v42.7.8`](https://redirect.github.com/pgjdbc/pgjdbc/blob/HEAD/CHANGELOG.md#4278-2025-09-18)

##### Added

- feat: Add configurable boolean-to-numeric conversion for ResultSet getters [PR #&#8203;3796](https://redirect.github.com/pgjdbc/pgjdbc/pull/3796)

##### Changed

- perf: remove QUERY\_ONESHOT flag when calling getMetaData [PR #&#8203;3783](https://redirect.github.com/pgjdbc/pgjdbc/pull/3783)
- perf: use `BufferedInputStream` with `FileInputStream` [PR #&#8203;3750](https://redirect.github.com/pgjdbc/pgjdbc/pull/3750)
- perf: enable server-prepared statements for DatabaseMetaData

##### Fixed

- fix: avoid NullPointerException when cancelling a query if cancel key is not known yet
- fix: Change "PST" timezone in TimestampTest to "Pacific Standard Time" [PR #&#8203;3774](https://redirect.github.com/pgjdbc/pgjdbc/pull/3774)
- fix: traverse the current dimension to get the correct pos in PgArray#calcRemainingDataLength [PR #&#8203;3746](https://redirect.github.com/pgjdbc/pgjdbc/pull/3746)
- fix: make sure getImportedExportedKeys returns columns in consistent order
- fix: Add "SELF\_REFERENCING\_COL\_NAME" field to getTables' ResultSetMetaData to fix NullPointerException [PR #&#8203;3660](https://redirect.github.com/pgjdbc/pgjdbc/pull/3660)
- fix: unable to open replication connection to servers < 12
- fix: avoid closing statement caused by driver's internal ResultSet#close()
- fix: return empty metadata for empty catalog names as it was before
- fix: Incorrect class comparison in PGXmlFactoryFactory validation

</details>

---

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Author: renovate-bot

samples/spring-data-jdbc/postgresql/pom.xml

@@ -72,7 +72,7 @@
     <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
-      <version>42.7.7</version>
+      <version>42.7.8</version>
     </dependency>
 
     <!-- Add OpenTelemetry for tracing and metrics. -->

samples/spring-data-mybatis/postgresql/pom.xml

@@ -75,7 +75,7 @@
     <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
-      <version>42.7.7</version>
+      <version>42.7.8</version>
     </dependency>
     <dependency>
       <groupId>org.testcontainers</groupId>