feat(serverless): support wait flag

[v1v]

Similarly done in the past with #226

What

• Support wait so it can be used in conjunction with oblt-cli/cluster-credentials
• Output the cluster-name

Usage

      - name: Get token
        id: get_token
        uses: tibdex/github-app-token@3beb63f4bd073e61482598c45c71c1019b59b73a # v2.1.0
        with:
          app_id: ${{ secrets.OBS_AUTOMATION_APP_ID }}
          private_key: ${{ secrets.OBS_AUTOMATION_APP_PEM }}
          permissions: >-
            {
              "contents": "write",
              "pull_requests": "read",
              "checks": "read"
            }
          repositories: >-
            ["observability-test-environments"]

      - uses: elastic/oblt-actions/git/setup@v1
        with:
          github-token: ${{ steps.get_token.outputs.token }}

      - name: Setup ephemeral cluster
        uses: elastic/oblt-actions/oblt-cli/cluster-create-serverless@v1
        id: cluster_create
        with:
          github-token: ${{ steps.get_token.outputs.token }}
          wait: 15
          [..]

      - name: Setup credentials for the ephemeral cluster
        uses: elastic/oblt-actions/oblt-cli/cluster-credentials@v1
        with:
          cluster-name: ${{ steps.cluster_create.outputs.cluster-name }}
          github-token: ${{ steps.get_token.outputs.token }}

[..]


      - name: Tear down ephemeral cluster
        uses: elastic/oblt-actions/oblt-cli/cluster-destroy@v1
        if: always()
        continue-on-error: true
        with:
          github-token: ${{ steps.get_token.outputs.token }}
          cluster-name: ${{ steps.cluster_create.outputs.cluster-name }}

[constanca-m]

Thank you so much for this!