fix: fix a deprecation warning that is shown when debug command is executed using node v10

[Fatme]

When tns debug ios command is executed with node10, a deprecation warning is shown

(node:93714) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/nativescript-cli/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
• Tests for the changes are included.

What is the current behavior?

Deprecation warning is shown when tns debug ios command is executed using node v10

What is the new behavior?

No deprecation warning is shown using node v10

[Fatme]

run ci