add rollup-plugin-url to support importing images

packages/create-freesewing-pattern/template/rollup.config.js

@@ -3,6 +3,7 @@ import commonjs from 'rollup-plugin-commonjs'
 import external from 'rollup-plugin-peer-deps-external'
 import postcss from 'rollup-plugin-postcss'
 import resolve from 'rollup-plugin-node-resolve'
+import url from 'rollup-plugin-url'
 
 import pkg from './package.json'
 
@@ -23,6 +24,7 @@ export default {
     postcss({
       modules: true
     }),
+    url(),
     babel({
       exclude: 'node_modules/**'
     }),