Bump testcontainers.version from 1.20.4 to 1.20.6 (#766)

Bumps `testcontainers.version` from 1.20.4 to 1.20.6.

Updates `org.testcontainers:postgresql` from 1.20.4 to 1.20.6
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.4...1.20.6)

Updates `org.testcontainers:oracle-xe` from 1.20.4 to 1.20.6
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.4...1.20.6)

Updates `org.testcontainers:mssqlserver` from 1.20.4 to 1.20.6
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.4...1.20.6)

---
updated-dependencies:
- dependency-name: org.testcontainers:postgresql
  dependency-type: direct:development
  update-type: version-update:semver-patch
- dependency-name: org.testcontainers:oracle-xe
  dependency-type: direct:development
  update-type: version-update:semver-patch
- dependency-name: org.testcontainers:mssqlserver
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pom.xml

@@ -66,7 +66,7 @@
         <jdbc.driver.firebird.version>4.0.9.java8</jdbc.driver.firebird.version>
         <junit.version>5.11.4</junit.version>
         <org.json.version>20250107</org.json.version>
-        <testcontainers.version>1.20.4</testcontainers.version>
+        <testcontainers.version>1.20.6</testcontainers.version>
         <testcontainers.firebird.version>1.5.1</testcontainers.firebird.version>
 
         <!--plugin versions -->