octokit.rest.actions not available

Start with the github-script v6 workflow entry point and the documented octokit.rest.actions.getEnvironmentVariable call shown in the reproduction. Compare the available github.rest.actions methods with the documented endpoint and run the supplied workflow to confirm the failure. Done means the documented call is available or the mismatch is clearly resolved.

Describe the bug

TypeError: github.rest.actions.getEnvironmentVariable is not a function
    at eval (eval at callAsyncFunction (/home/runner/work/_actions/actions/github-script/v6/dist/index.js:15099:16), <anonymous>:3:43)
    at callAsyncFunction (/home/runner/work/_actions/actions/github-script/v6/dist/index.js:15100:12)
    at main (/home/runner/work/_actions/actions/github-script/v6/dist/index.js:15[19](https://github.com/g2crowd/actions_test/actions/runs/4372190858/jobs/7648818737#step:2:20)8:26)
    at /home/runner/work/_actions/actions/github-script/v6/dist/index.js:15175:1
    at /home/runner/work/_actions/actions/github-script/v6/dist/index.js:15230:3
    at Object.<anonymous> (/home/runner/work/_actions/actions/github-script/v6/dist/index.js:15233:12)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:8[22](https://github.com/g2crowd/actions_test/actions/runs/4372190858/jobs/7648818737#step:2:23):12)
Error: Unhandled error: TypeError: github.rest.actions.getEnvironmentVariable is not a function

To Reproduce

jobs:
  check-env:
    name: Validate Environment Configuration
    environment: staging
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v6
        with:
          script: |
            const sidecar = await github.rest.actions.getEnvironmentVariable({
              repository_id: context.repo.id,
              environment_name: context.payload.client_payload.environment,
              name: 'SIDECAR'
            });
            console.log(JSON.stringify(sidecar));
            return;

Expected behavior
github.rest.actions.getEnvironmentVariable should be defined as documented in octokit/rest