fix: fix conversion from int to float64 (#753)

* fix: fix conversion from int to float64

* fix: fix a compile error

```
cannot convert v (variable of type interface{}) to type float64: need type assertion
```

interpreter.go

@@ -977,8 +977,16 @@ func jsonToValue(i *interpreter, v interface{}) (value, error) {
 
  case bool:
  return makeValueBoolean(v), nil
- case int, int8, int16, int32, int64:
- return makeDoubleCheck(i, v.(float64))
+ case int:
+ return makeDoubleCheck(i, float64(v))
+ case int8:
+ return makeDoubleCheck(i, float64(v))
+ case int16:
+ return makeDoubleCheck(i, float64(v))
+ case int32:
+ return makeDoubleCheck(i, float64(v))
+ case int64:
+ return makeDoubleCheck(i, float64(v))
  case float64:
  return makeDoubleCheck(i, v)