[jb] bump up major platform version of backend plugin

[akosyakov]

Description

Update the major version of the backend plugin to unblock auto upgrade of latest images.

Related Issue(s)

Fixes #

How to test

• Test stable version in the preview env:
  • you should see custom metrics in the backend control center, i.e. workspace CPU
  • configured tasks should be attached
  • there should not be notifications about internal IDE ports
• It is not possible to test latest, since images are out dated.
  • Start a Gitpod workspace for this PR with IntelliJ.
  • Run ./launch-dev-server.sh u from components/ide/jetbrains/backend-plugin/
  • Copy Gitpod link from output and open in Browser.
  • Do tests similar for stable.

Release Notes

NONE

Documentation

Build Options:

• /werft with-werft
  Run the build with werft instead of GHA
• leeway-no-cache
• /werft no-test
  Run Leeway with --dont-test

Publish Options

• /werft publish-to-npm
• /werft publish-to-jb-marketplace

Installer Options

• with-ee-license
• with-dedicated-emulation
• with-ws-manager-mk2
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment Options:

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-gce-vm
  If enabled this will create the environment on GCE infra
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh

[werft-gitpod-dev-com]

started the job as gitpod-build-ak-jb-backend-upgrade.2 because the annotations in the pull request description changed
(with .werft/ from main)