Growth Analysis, and Yield Responses of Millet (&amp;lt;i&amp;gt;Pennisetum glaucum (L.) R. Br.&amp;lt;/i&amp;gt;) and Cowpea (&amp;lt;i&amp;gt;Vigna unguiculata&amp;lt;/i&amp;gt; [L.] Walp) in an Intercropping System