feat(bs5): Replace .btn-block with utility classes

Keep prop for backwards compat

src/Button.js

@@ -71,7 +71,7 @@ class Button extends React.Component {
       close || 'btn',
       close || btnOutlineColor,
       size ? `btn-${size}` : false,
-      block ? 'btn-block' : false,
+      block ? 'd-block w-100' : false,
       { active, disabled: this.props.disabled }
     ), cssModule);
 

src/__tests__/Button.spec.js

@@ -94,7 +94,7 @@ describe('Button', () => {
   it('should render block level buttons', () => {
     const block = shallow(<Button block>Block Level Button</Button>);
 
-    expect(block.hasClass('btn-block')).toBe(true);
+    expect(block.hasClass('d-block w-100')).toBe(true);
   });
 
   it('should render close icon utility with default props', () => {