remove mention of trick or trace in readme

[LimesKey]

Submission Checklist:

• [ ] I am a current high school, middle school, or home schooled student.

  • [ ] I am 18 or under
  • [ ] I have filled out the verification form (do this for every pull request)
  • or the legacy verification form if the above doesn't work

• [ ] I have joined the #electronics channel on Slack

• [ ] I made this board from scratch, even if I followed a tutorial

• [ ] I have followed the directions in README.md

  • [ ] Created a folder under onboard/projects
  • [ ] Filled out TEMPLATE.md as README.md inside your project folder
  • [ ] Uploaded gerber.zip and schematic.pdf inside your project folder
  • [ ] Created a folder called src and uploaded design files
  • [ ] Uploaded screenshot of PCB order called cart.png with all costs included
  • [ ] I am ordering the smallest batch size (ie. JLCPCB's smallest order is for 5 boards)
  • [ ] If outside the US I've checked that I can afford the customs charges in my country (which isn't covered by the grant)

• [ ] (Optional) This project is from a tutorial[^1].

• [ ] (Optional) This project is for OnBoard Live[^2].

• [ ] (Optional) This project is for Trick or Trace[^3].

• [ ] (Optional) I'm in a FIRST (FRC, FTC, FLL, etc.) team. The number is: ____

[^1]: Projects from a tutorial are 100% fine! We just want to ask so we can count how people are using tutorials. [^2]: OnBoard Live is a special version of OnBoard where you can earn more money for designing advanced boards. Check out the #onboard-live channel on our Slack! [^3]: Trick or Trace is a limited time design contest for PCBs, enter your PCB into one of the three catagories and by peer voting, get chosen for a 100$ additional grant from OnBoard.