93 update chainge link

[brklyn8900]

Resolves #93

Brief description

Update the Where to get KOIN section with a link to the Chainge and Uniswap apps.

Checklist

• [ ] I have built this pull request locally
• [ ] I have ran the unit tests locally
• [ ] I have manually tested this pull request
• [ ] I have reviewed my pull request
• [ ] I have added any relevant tests

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