ci: upgrade Node.js from EOL v18 to v20 in update workflows

[Ankitsinghsisodya]

Problem

The following workflows use Node.js 18, which reached End of Life in April 2024:

• .github/workflows/update-ca-bundle.yaml
• .github/workflows/update-quarkus-platform.yaml
• .github/workflows/update-springboot-platform.yaml

Running on an EOL Node.js version means no security patches and potential compatibility issues with newer packages.

Fix

• Upgrade node-version: 18 → node-version: "20"

[Ankitsinghsisodya]

/assign