Fix: features.md

[kaitoii11]

Reason for Change:

Fix outdated content for Custom VNet.

Issue Fixed:

Fix #4098

Credit Where Due:

Does this change contain code from or inspired by another project?

• No
• Yes

If "Yes," did you notify that project's maintainers and provide attribution?

• No
• Yes

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

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[kaitoii11]

/assign @jadarsie

[jackfrancis]

/lgtm

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