updatecli: dynamic specs

[v1v]

What does this PR do?

• Use values.yml to define the configuration to be used when running the updatecli apply, see https://www.updatecli.io/docs/commands/updatecli_apply/#updatecli-apply
• Use updatecli scm to fetch the specs in elastic/apm and elastic/apm-data under the different folders.
• To update those files, use tar with the shell target.

Test

CI

See https://github.com/elastic/apm-agent-ruby/actions/runs/7652598237 that created https://github.com/elastic/apm-agent-ruby/pull/1438/files

Locally:

GITHUB_WORKSPACE=/tmp \
  PATH=/opt/homebrew/bin:$PATH \
  GIT_USER="Victor Martinez" \
  GIT_EMAIL="[email protected]" \
  GITHUB_TOKEN=$(gh auth token) \
  updatecli apply --config .ci/updatecli/updatecli.d --values .ci/updatecli/values.yml --debug

or without pushing any changes

GITHUB_WORKSPACE=/tmp \
  PATH=/opt/homebrew/bin:$PATH \
  GIT_USER="Victor Martinez" \
  GIT_EMAIL="[email protected]" \
  GITHUB_TOKEN=$(gh auth token) \
  updatecli apply --config .ci/updatecli/updatecli.d --values .ci/updatecli/values.yml --push=false --debug

additionally, you can change the org from elastic to your own GitHub avatar.

Checklist

• I have signed the Contributor License Agreement.
• My code follows the style guidelines of this project (See .rubocop.yml)
• I have rebased my changes on top of the latest main branch

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

• I have made corresponding changes to the documentation
• I have updated CHANGELOG.asciidoc
• I have updated supported-technologies.asciidoc
• Added an API method or config option? Document in which version this will be introduced