CI: Update kanga333/variable-mapper to a version that uses Node.js 20+

[kaylareopelle]

The version of kanga333/variable-mapper we use in our workflows runs on Node 16. This adds a deprecation warning annotation to our runs, for example:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: kanga333/variable-mapper@. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

Update the version of kanga333/variable-mapper used in all our workflows to a version that uses Node.js 20 or higher. At the time of creating this ticket, Node.js 22 was the most recent version.

• August 2nd, 2024 - this action needs to be updated to use Node20+. See this conversation.

[workato-integration]

https://new-relic.atlassian.net/browse/NR-262223