test: Appveyor configuration (#1000)
test: Appveyor configuration (#1000)

This enables Windows-based CI testing
sehrope/pgjdbc,davecramer/pgjdbc,lordnelson/pgjdbc,lordnelson/pgjdbc,whitingjr/pgjdbc,golovnin/pgjdbc,whitingjr/pgjdbc,sehrope/pgjdbc,golovnin/pgjdbc,davecramer/pgjdbc,marschall/pgjdbc,AlexElin/pgjdbc,lordnelson/pgjdbc,jorsol/pgjdbc,marschall/pgjdbc,AlexElin/pgjdbc,sehrope/pgjdbc,zemian/pgjdbc,AlexElin/pgjdbc,zemian/pgjdbc,pgjdbc/pgjdbc,jorsol/pgjdbc,golovnin/pgjdbc,davecramer/pgjdbc,marschall/pgjdbc,pgjdbc/pgjdbc,pgjdbc/pgjdbc,sehrope/pgjdbc,marschall/pgjdbc,zemian/pgjdbc,davecramer/pgjdbc,whitingjr/pgjdbc,jorsol/pgjdbc,zapov/pgjdbc,pgjdbc/pgjdbc,jorsol/pgjdbc,zapov/pgjdbc,zapov/pgjdbc