Ability to use Waves

[giseburt]

This is a paired-down version of #376

Would like the ability to use Waves, as in the following modified test case:

    const pipeline = new GitHubWorkflow(app, 'Pipeline', {
      workflowPath: `${dir}/.github/workflows/deploy.yml`,
      synth: new ShellStep('Build', {
        installCommands: ['yarn'],
        commands: ['yarn build'],
      }),
      jobSettings: {
        if: "contains(github.event.issue.labels.*.name, 'deployToA') || contains(github.event.issue.labels.*.name, 'deployToB')",
      },
    });

    // Make a wave to have the stages be parallel (not depend on each other)
    const wave = pipeline.addWave('MyWave', {
      pre: [
        new GitHubActionStep('PreWaveAction', {
          jobSteps: [
            {
              name: 'pre wave action',
              uses: '[email protected]',
              with: {
                'app-id': 1234,
                'secrets': 'my-secrets',
              },
            },
          ],
        }),
      ],

      post: [
        new GitHubActionStep('PostWaveAction', {
          jobSteps: [
            {
              name: 'Checkout',
              uses: 'actions/checkout@v3',
            },
            {
              name: 'post wave action',
              uses: '[email protected]',
              with: {
                'app-id': 4321,
                'secrets': 'secrets',
              },
            },
          ],
        }),
      ],
    });

    const stageA = new GitHubStage(app, 'MyStageA', {
      env: { account: '111111111111', region: 'us-east-1' },
      jobSettings: {
        if: "success() && contains(github.event.issue.labels.*.name, 'deployToA')",
      },
    });
    new Stack(stageA, 'MyStackA');

    const stageB = new GitHubStage(app, 'MyStageB', {
      env: { account: '12345678901', region: 'us-east-1' },
      gitHubEnvironment: 'test',
    });
    new Stack(stageB, 'MyStackB');

    wave.addStage(stageA);
    wave.addStage(stageB);

Currently we lose the ability to use GitHubActionStep in pre and post as well as any AddGitHubStageOptions values not inherited from StageProps.

[vincentgna]

any update? We are currently using the suggested hack:

           const options: AddGitHubStageOptions = {
                jobSettings: {
                    if: `always() &&\n!contains(needs.*.result, 'failure') &&\n!contains(needs.*.result, 'cancelled') &&\ngithub.ref_name == ${env.branch}`,
                },
            }

to decouple dependency between stages, but it would be nicer to use a wave

[giseburt]

Progress is being made on the PR #490