feat: export defaul theme

src/defaultTheme.js

@@ -0,0 +1,7 @@
+import inputRangeTheme from './components/InputRange/defaultTheme.json';
+import legendRangeTheme from './components/Legend/defaultTheme.json';
+
+export default {
+  ...inputRangeTheme,
+  ...legendRangeTheme
+};

src/index.js

@@ -9,3 +9,4 @@ export { default as Dropdown } from './components/Dropdown';
 export { default as MonthPicker } from './components/MonthPicker';
 export { default as YearPicker } from './components/YearPicker';
 export { default as Legend } from './components/Legend';
+export { default as defaultTheme } from './defaultTheme';