chore: fix README capitalization (Icon -> ICON)

[rhizome-labs]

Closes #ISSUE-NUMBER

Checklist:

• [ ] I have performed a self-review of my own code
• [ ] I have documented my code in accordance with the documentation guidelines
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have run the unit tests
• [ ] I only have one commit (if not, squash them into one commit).
• [ ] I have a descriptive commit message that adheres to the commit message guidelines

Please review the CONTRIBUTING.md file for detailed contributing guidelines.

[codecov[bot]]

Codecov Report

Merging #735 (039bbcc) into main (ed4e38c) will decrease coverage by 0.04%. The diff coverage is n/a.

@@             Coverage Diff              @@
##               main     #735      +/-   ##
============================================
- Coverage     42.06%   42.02%   -0.05%     
  Complexity      801      801              
============================================
  Files           115      115              
  Lines         11330    11330              
  Branches        941      941              
============================================
- Hits           4766     4761       -5     
- Misses         6154     6159       +5     
  Partials        410      410              

Impacted Files	Coverage Δ
cmd/iconbridge/chain/bsc/receiver.go	57.80% <0.00%> (-1.22%)	:arrow_down:

[CyrusVorwald]

@all-contributors please add @rhizome-labs for content

[allcontributors[bot]]

@CyrusVorwald-ICON

I've put up a pull request to add @rhizome-labs! :tada: