doc: update the merge requirement for tck

[CodeLeom]

Description:
update the merge requirement for sdk tck

Related issue(s):
closes 235
Fixes #
#235
Notes for reviewer:

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[CodeLeom]

@rwalworth I had to open a new PR. I closed the previous PR and reopen another. I followed the last instruction, but I noticed it reverted the changes back to the initial and the merge was now done automatic. It will be merged completed but it will be realized in the future, so I had to close the PR and reopen this.

[jsync-swirlds]

@rwalworth I had to open a new PR. I closed the previous PR and reopen another. I followed the last instruction, but I noticed it reverted the changes back to the initial and the merge was now done automatic. It will be merged completed but it will be realized in the future, so I had to close the PR and reopen this.

It can be tricky to meet Github GPG and DCO requirements after the fact. For a simple PR, in particular, this close-and-reopen-with-fixed-commit is often the easiest solution.

[rwalworth]

Appreciate the effort and for going through the headache of signing commits, still LGTM!