feat(ngModelAttrsManipulator): step attribute

Closes #592

Author: Kamil Kisiela

src/run/formlyNgModelAttrsManipulator.js

@@ -182,7 +182,7 @@ function addFormlyNgModelAttrsManipulator(formlyConfig, $interpolate) {
     const bothBooleanAndBound = ['required', 'disabled']
     const bothAttributeAndBound = ['pattern', 'minlength']
     const statementOnly = ['change', 'keydown', 'keyup', 'keypress', 'click', 'focus', 'blur']
-    const attributeOnly = ['placeholder', 'min', 'max', 'tabindex', 'type']
+    const attributeOnly = ['placeholder', 'min', 'max', 'step', 'tabindex', 'type']
     if (formlyConfig.extras.ngModelAttrsManipulatorPreferUnbound) {
       bothAttributeAndBound.push('maxlength')
     } else {

src/run/formlyNgModelAttrsManipulator.test.js

@@ -258,7 +258,7 @@ describe('formlyNgModelAttrsManipulator', () => {
 
     describe(`attributeOnly`, () => {
 
-      ['placeholder', 'min', 'max', 'tabindex', 'type'].forEach(testAttribute)
+      ['placeholder', 'min', 'max', 'step', 'tabindex', 'type'].forEach(testAttribute)
 
       function testAttribute(name) {
         it(`should be placed as an attribute if it is present in the templateOptions`, () => {