Update image_recipe.md

[phrogg]

Updated link format, as the other one threw this error on me:

• Description of what the PR does, such as fixes # {issue number}

  pi@picroft:~ $ wget -N https://rawgit.com/MycroftAI/enclosure-picroft/buster/home/pi/update.sh
  --2022-12-14 08:52:50--  https://rawgit.com/MycroftAI/enclosure-picroft/buster/home/pi/update.sh
  Resolving rawgit.com (rawgit.com)... 0.0.0.0, ::
  Connecting to rawgit.com (rawgit.com)|0.0.0.0|:443... failed: Connection refused.
  Connecting to rawgit.com (rawgit.com)|::|:443... failed: Connection refused.

• Description of how to validate or test this PR

• Run the install script.

• Whether you have signed a CLA (Contributor Licensing Agreement) I'm willing to but didn't find it yet :P

[krisgesling]

Thanks Phil,

We should indeed move away from rawgit... https://rawgit.com/

Are you happy to sign our CLA?

[phrogg]

Sure thing! And merry Christmas :) I think your link to the CLA is not working correctly though, also I cannot find a CONTRIBUTING.md in the repo.