Update ReadMe.md

[AndrewKeepCoding]

Fixes

This PR adds missing emoji to align with other level 2 headers.

PR Type

What kind of change does this PR introduce?

• Documentation content changes

What is the current behavior?

What is the new behavior?

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• [x] Based off latest main branch of toolkit
• [ ] Tested code with current supported SDKs
• [ ] New component
  • [ ] Documentation has been added
  • [ ] Sample in sample app has been added
  • [ ] Analyzers are passing for documentation and samples
  • [ ] Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• [ ] Tests for the changes have been added (if applicable)
• [ ] Header has been added to all new source files
• [x] Contains NO breaking changes

Other information

[Arlodotexe]

Ideally, we'd have the actual toolkit logo here. The emoji is an approximation that feels a bit too gimmicky to place next to the name of the app.

[AndrewKeepCoding]

@Arlodotexe I replaced the emoji with the app icon. What do you think?