doc: remove outdated COLLABORATOR_GUIDE sentence about breaking changes
The TSC has delegated authority over LTS and Current branches to the Release WG. Remove the bullet point about TSC having authority to determine that a breaking change is necessary on LTS and Current release branches. Retaining that authority would require de-chartering the Release WG.
Fixes: https://github.com/nodejs/TSC/issues/660
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines