Fix issue #15

[shhdharmen]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: #15

What is the new behavior?

• Fixes grouping
• Introduces new builder pattern to achieve pre-grouping

  const parentBuilder = new HotToastBuilder(ngTemplateGroup, toast)
  .setOptions({
    position: 'top-right',
    autoClose: false,
    className: 'hot-toast-custom-class',
    group: {
      className: 'hot-toast-custom-class'
    }
  });
  
  // Create child toasts
  const children = childNotifications(ngTemplateGroupItem).map((child) => {
    return new HotToastBuilder(child.options.message, toast)
      .setOptions(child.options);
  });
  
  // Add children to parent
  children.forEach((child) => parentBuilder.addChild(child));
  
  // Create the toast with all children (but don't show yet)
  const parentRef = parentBuilder.create();
  
  // Once all refs are attached, show the parent toast
  parentRef.afterGroupRefsAttached.subscribe(() => {
    parentRef.show();
  });

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[github-actions]

🎉 This PR is included in version 3.1.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[shhdharmen]

🎉 This PR is included in version 3.1.0-beta.3 🎉

The release is available on:

• npm package (@beta dist-tag)
• GitHub release

Your semantic-release bot 📦🚀