Bump integration branch to next release (6.7.x)

[tishun]

As part of #3281

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[Copilot]

Pull Request Overview

This PR updates the dependency version referenced in the documentation to reflect a new release.

• Updates version numbers in Maven (pom.xml), Ivy (ivy.xml), and Gradle (build.gradle) examples.
• The new version appears as 6.6.0.RELEASE in the examples.

Files not reviewed (1)

• pom.xml: Language not supported

Comments suppressed due to low confidence (3)

docs/getting-started.md:15

• The Maven dependency version is updated to 6.6.0.RELEASE, but the PR title indicates a bump to 6.7.x. Please verify that the documentation reflects the intended release version.

+    <version>6.6.0.RELEASE</version>

docs/getting-started.md:26

• The ivy.xml dependency version is updated to 6.6.0.RELEASE. This differs from the expected 6.7.x mentioned in the PR title, so please confirm if this discrepancy is intentional.

+    <dependency org="io.lettuce" name="lettuce-core" rev="6.6.0.RELEASE"/>

docs/getting-started.md:37

• The Gradle dependency version is set to 6.6.0.RELEASE, which may not align with the integration branch bump to 6.7.x as stated in the PR title. Please verify the intended version.

+  implementation 'io.lettuce:lettuce-core:6.6.0.RELEASE'