fix some lint errors

Author: ekratskih

components/form/button-group/ButtonGroup.es6.js

@@ -1,4 +1,5 @@
 import * as React from 'react'
+import PropTypes from 'prop-types'
 import classnames from 'classnames'
 
 function ButtonGroup ({ vertical, className, children }) {
@@ -12,4 +13,10 @@ function ButtonGroup ({ vertical, className, children }) {
   )
 }
 
+ButtonGroup.propTypes = {
+  vertical: PropTypes.bool,
+  className: PropTypes.string,
+  children: PropTypes.node
+}
+
 export default ButtonGroup

components/form/checkbox/Checkbox.es6.js

@@ -1,4 +1,5 @@
 import React from 'react'
+import PropTypes from 'prop-types'
 import classnames from 'classnames'
 
 import { Checkmark } from '../../Icons.es6.js'
@@ -34,6 +35,16 @@ function Checkbox ({ disabled, checked, indeterminate, label, name, onChange, ha
   )
 }
 
+Checkbox.propTypes = {
+  disabled: PropTypes.bool,
+  checked: PropTypes.bool,
+  indeterminate: PropTypes.bool,
+  label: PropTypes.string,
+  name: PropTypes.string,
+  onChange: PropTypes.func,
+  hasError: PropTypes.bool
+}
+
 Checkbox.defaultProps = {
   label: '',
   name: '',

components/form/checkbox/CheckboxSelect.es6.js

@@ -1,4 +1,5 @@
 import React from 'react'
+import PropTypes from 'prop-types'
 import { isEqual } from 'lodash'
 
 import Checkbox from '../checkbox/Checkbox.es6.js'
@@ -47,6 +48,16 @@ function CheckboxSelect ({ checked, disabled, label, onChange, onSelectChange,
   )
 }
 
+CheckboxSelect.propTypes = {
+  checked: PropTypes.bool,
+  disabled: PropTypes.bool,
+  label: PropTypes.string,
+  onChange: PropTypes.func,
+  onSelectChange: PropTypes.func,
+  selectOptions: PropTypes.array,
+  selectedOption: PropTypes.object
+}
+
 CheckboxSelect.defaultProps = {
   checked: false,
   disabled: false,