Update deprecated Angular CLI Command

[RicardoVaranda]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[X] Documentation content changes
[ ] angular.io application / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

If you try to run it with:
ng build --prod --sourcemaps

You get the following error message:
Unknown option: '--sourcemaps'

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

[brandonroberts]

LGTM. Update your git commit message to follow the guidelines: "docs: update Angular CLI option for sourcemaps"

[ngbot]

I see that you just added the PR action: merge label, but the following checks are still failing:
     status "continuous-integration/travis-ci/pr" is failing

If you want your PR to be merged, it has to pass all the CI checks.

If you can't get the PR to a green state due to flakes or broken master, please try rebasing to master and/or restarting the CI job. If that fails and you believe that the issue is not due to your change, please contact the caretaker and ask for help.

[RicardoVaranda]

Hi @brandonroberts , I've committed the required changes but it seems travis is still failing due to timeout, would you mind having a look?

[brandonroberts]

Sure @RicardoVaranda. The caretaker will get it merged if Travis keeps being flakey. I'll run it again to see if it passes

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}