FIx ToStringMapStringSliceE

* Update caste.go

bug fix

json config, for example:
{ "test" : ["abc", "123"] }

* update test

cast_test.go

@@ -108,6 +108,9 @@ func TestMaps(t *testing.T) {
 	var stringMapStringSliceMultiple = map[string][]string{"key 1": []string{"value 1", "value 2", "value 3"}, "key 2": []string{"value 1", "value 2", "value 3"}, "key 3": []string{"value 1", "value 2", "value 3"}}
 	var stringMapStringSliceSingle = map[string][]string{"key 1": []string{"value 1"}, "key 2": []string{"value 2"}, "key 3": []string{"value 3"}}
 
+	var stringMapInterface1 = map[string]interface{}{"key 1": []string{"value 1"}, "key 2": []string{"value 2"}}
+	var stringMapInterfaceResult1 = map[string][]string{"key 1": []string{"value 1"}, "key 2": []string{"value 2"}}
+
 	assert.Equal(t, ToStringMap(taxonomies), map[string]interface{}{"tag": "tags", "group": "groups"})
 	assert.Equal(t, ToStringMapBool(stringMapBool), map[string]bool{"v1": true, "v2": false})
 
@@ -128,6 +131,7 @@ func TestMaps(t *testing.T) {
 	assert.Equal(t, ToStringMapStringSlice(interfaceMapInterfaceSlice), stringMapStringSlice)
 	assert.Equal(t, ToStringMapStringSlice(interfaceMapString), stringMapStringSingleSliceFieldsResult)
 	assert.Equal(t, ToStringMapStringSlice(interfaceMapInterface), stringMapStringSingleSliceFieldsResult)
+	assert.Equal(t, ToStringMapStringSlice(stringMapInterface1), stringMapInterfaceResult1)
 }
 
 func TestSlices(t *testing.T) {

caste.go

@@ -310,7 +310,14 @@ func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
 		}
 	case map[string]interface{}:
 		for k, val := range v {
-			m[ToString(k)] = []string{ToString(val)}
+			switch vt := val.(type) {
+			case []interface{}:
+				m[ToString(k)] = ToStringSlice(vt)
+			case []string:
+				m[ToString(k)] = vt
+			default:
+				m[ToString(k)] = []string{ToString(val)}
+			}
 		}
 		return m, nil
 	case map[interface{}][]string: