Update charts and configs

[Pavani-Panakanti]

What type of PR is this?
release workflow

Which issue does this PR fix?:
release workflow

What does this PR do / Why do we need it?:
release

Testing done on this change:
release testing

Will this PR introduce any new dependencies?:
No

Will this break upgrades or downgrades? Has updating a running cluster been tested?:
No

Does this change require updates to the CNI daemonset config files to work?:
No

Does this PR introduce any user-facing change?:
No

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Copilot]

Pull Request Overview

This PR updates charts and configurations for a release workflow, bumping version tags from v1.20.1 to v1.20.2 for VPC CNI components and from v1.2.4 to v1.2.6 for the node agent.

• Updates VPC CNI version from v1.20.1 to v1.20.2 across all configuration files
• Updates node agent version from v1.2.4 to v1.2.6
• Adds changelog entries for v1.20.2 release

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
scripts/run-cni-release-tests.sh	Updates CNI metrics helper image references to v1.20.2
scripts/generate-cni-yaml.sh	Updates VPC_CNI_VERSION and NODE_AGENT_VERSION variables
config/master/*.yaml	Updates container image tags for all regional configurations
charts/*/values.yaml	Updates default image tags in Helm chart values
charts/*/README.md	Updates documentation to reflect new version tags
charts/*/Chart.yaml	Updates chart version and appVersion metadata
CHANGELOG.md	Adds release notes for v1.20.2

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