update README to refer to shiny new docs
update README to refer to shiny new docs

beni55/sqlx,outrightmental/go-sqlx,cortex/sqlx,adcaes/sqlx,larsth/sqlx,wmydz1/sqlx,johnsto/sqlx,StabbyCutyou/sqlx,proteneer/sqlx,snikch/sqlx,aiyi/sqlx,jmoiron/sqlx