Add merch code amounts for community PRs

[charlescook-ph]

Suggested we include how much we actually give out as a merch code, and changed text as it seems the bot doesn't automatically send a code but rather asks the person to email hey@

Checklist

• [ ] Titles are in sentence case
• [ ] Feature names are in title case
• [ ] Words are spelled using American English
• [ ] I have checked out our style guide

[joethreepwood]

Auto merging as this seems an obvious one.