Bump org.postgresql:postgresql in /testing/testcontainers/java

Bumps [org.postgresql:postgresql](https://github.com/pgjdbc/pgjdbc) from 42.7.7 to 42.7.8.
- [Release notes](https://github.com/pgjdbc/pgjdbc/releases)
- [Changelog](https://github.com/pgjdbc/pgjdbc/blob/master/CHANGELOG.md)
- [Commits](pgjdbc/pgjdbc@REL42.7.7...REL42.7.8)

---
updated-dependencies:
- dependency-name: org.postgresql:postgresql
  dependency-version: 42.7.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

testing/testcontainers/java/build.gradle

@@ -20,7 +20,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'org.postgresql:postgresql:42.7.7'
+    implementation 'org.postgresql:postgresql:42.7.8'
     implementation 'io.crate:crate-jdbc:2.7.0'
     implementation 'org.slf4j:slf4j-api:2.0.17'
     implementation 'org.slf4j:slf4j-simple:2.0.17'