Fix typo in document

[tom--bo]

A Pull Request should be associated with an Issue.

We wish to have discussions in Issues. A single issue may be targeted by multiple PRs.
If you're offering a new feature or fixing anything, we'd like to know beforehand in Issues,
and potentially we'll be able to point development in a particular direction.

Related issue: none (just one typo in document)

Thank you! We are open to PRs, but please understand if for technical reasons we are unable to accept each and any PR

Description

This PR [briefly explain what is does]

Sample command is not correct in here

orchestrator -c ...

should be

orchestrator-client -c ...

In case this PR introduced Go code changes:

• contributed code is using same conventions as original code
• code is formatted via gofmt (please avoid goimports)
• code is built via ./build.sh
• code is tested via go test ./go/...

Only small fix in docs.

[shlomi-noach]

Thanks!

[shlomi-noach]

Sorry about the delay; I expect to look into & merge a bunch of community PRs during the first two weeks of October.