RFR: 7267: Change artifact id from "org.openjdk.jmc.agent" to "agent"

[Guru Hb]

On Wed, 9 Jun 2021 18:59:58 GMT, Patrick Reinhart <reinhapa at openjdk.org> wrote:

> - Changes the current artifact id from `org.openjdk.jmc.agent` to `agent`
> - Changes all agent artifact/version references within command line arguments accordingly

+1

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Marked as reviewed by ghb (Reviewer).

PR: https://git.openjdk.java.net/jmc/pull/261