Add exportloopref linter (#1163)

Author: sayboras

go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/golangci/unconvert v0.0.0-20180507085042-28b1c447d1f4
 	github.com/jingyugao/rowserrcheck v0.0.0-20191204022205-72ab7603b68a
 	github.com/jirfag/go-printf-func-name v0.0.0-20191110105641-45db9963cdd3
+	github.com/kyoh86/exportloopref v0.1.4
 	github.com/maratori/testpackage v1.0.1
 	github.com/matoous/godox v0.0.0-20190911065817-5d6d842e92eb // v1.0
 	github.com/mattn/go-colorable v0.1.6