add build_mapping_tables.R to .Rbuildignore
add build_mapping_tables.R to .Rbuildignore

kevinykuo/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr,rstudio/sparklyr,rstudio/sparklyr,kevinykuo/sparklyr,kevinykuo/sparklyr,rstudio/sparklyr