readme: installation instructions mention compatible node versions
readme: installation instructions mention compatible node versions

sammcj/groovebasin,neynah/groovebasin,sammcj/groovebasin,gorlug/groovebasin,Qbuer/groovebasin,CalebMorris/groovebasin,andrewrk/groovebasin,neynah/groovebasin,emersion/groovebasin,andrewrk/groovebasin,Qbuer/groovebasin,neynah/groovebasin,andrewrk/groovebasin,CalebMorris/groovebasin,CalebMorris/groovebasin,melissanoelle/groovebasin,dwrensha/groovebasin,sammcj/groovebasin,emersion/groovebasin,dwrensha/groovebasin,dwrensha/groovebasin,dwrensha/groovebasin,Qbuer/groovebasin,gorlug/groovebasin,melissanoelle/groovebasin,gorlug/groovebasin,emersion/groovebasin,melissanoelle/groovebasin