add metadata upsert test case
add metadata upsert test case

joeferraro/jsforce,lkatney/jsforce,kimchouard/jsforce,jsforce/jsforce,saleswise/jsforce,jdcrensh/jsforce,bhaskarmelkani/jsforce,lkatney/jsforce,pcon/jsforce,saleswise/jsforce,jdcrensh/jsforce,jsforce/jsforce,saleswise/jsforce,joeferraro/jsforce,rdietrick/jsforce,jesperkristensen/jsforce,pcon/jsforce,jsforce/jsforce,parthiban019/jsforce,pcon/jsforce,nutthawan/jsforce,bhaskarmelkani/jsforce,nutthawan/jsforce,jesperkristensen/jsforce,parthiban019/jsforce