Amend examples (#211)

examples/currency/history/go/historicRatesForACurrency.go

@@ -0,0 +1,17 @@
+package example
+
+import (
+	"fmt"
+	"github.com/micro/services/clients/go/currency"
+	"os"
+)
+
+// Returns the historic rates for a currency on a given date
+func HistoricRatesForAcurrency() {
+	currencyService := currency.NewCurrencyService(os.Getenv("MICRO_API_TOKEN"))
+	rsp, err := currencyService.History(&currency.HistoryRequest{
+		Code: "USD",
+		Date: "2021-05-30",
+	})
+	fmt.Println(rsp, err)
+}