Merge pull request #133 from etpinard/updates-for-dash2

Updates for Dash 2.0

Author: alexcjohnson

{{cookiecutter.project_shortname}}/requirements.txt

@@ -1,2 +1,2 @@
 # dash is required to call `build:py`
-dash[dev]>=1.15.0
+dash[dev]>=2.0.0

{{cookiecutter.project_shortname}}/usage.py

@@ -1,9 +1,7 @@
 import {{cookiecutter.project_shortname}}
-import dash
-from dash.dependencies import Input, Output
-import dash_html_components as html
+from dash import Dash, callback, html, Input, Output
 
-app = dash.Dash(__name__)
+app = Dash(__name__)
 
 app.layout = html.Div([
     {{cookiecutter.project_shortname}}.{{cookiecutter.component_name}}(
@@ -15,7 +13,7 @@
 ])
 
 
-@app.callback(Output('output', 'children'), [Input('input', 'value')])
+@callback(Output('output', 'children'), Input('input', 'value'))
 def display_output(value):
     return 'You have entered {}'.format(value)