chore: update running-locally.md - corrects protoc install command

[aistein]

According to the doc which is currently linked in - one is to install protoc via brew install protobuf, and not via brew install protoc.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
• I've signed the CLA.
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My builds are green. Try syncing with master if they are not.
• My organization is added to USERS.md.

[CLAassistant]

All committers have signed the CLA.

[aistein]

/review @alexec