fix: update sass (#787)

Author: blackwolf3342

app/templates/_package.json

@@ -36,7 +36,7 @@
     "gulp-plumber": "^1.2.1",
     "gulp-postcss": "^8.0.0",
     <%_ if (includeSass) { -%>
-    "gulp-sass": "^4.0.2",
+    "gulp-sass": "^5.1.0",
     <%_ } -%>
     "gulp-size": "^3.0.0",
     "gulp-uglify": "^3.0.2",
@@ -45,6 +45,9 @@
     "mkdirp": "^0.5.1",
     <%_ } -%>
     "mocha": "^6.1.4",
+    <%_ if (includeSass) { -%>
+    "sass": "^1.58.3",
+    <%_ } -%>
     "yargs": "13.2.4"
   },
   "scripts": {

app/templates/gulpfile.js

@@ -9,6 +9,9 @@ const Modernizr = require('modernizr');
 const browserSync = require('browser-sync');
 const del = require('del');
 const autoprefixer = require('autoprefixer');
+<%_ if (includeSass) { -%>
+const sass = require('gulp-sass')(require('sass'));
+<%_ } -%>
 const cssnano = require('cssnano');
 const { argv } = require('yargs');
 
@@ -27,11 +30,11 @@ function styles() {
     sourcemaps: !isProd,
   })
     .pipe($.plumber())
-    .pipe($.sass.sync({
+    .pipe(sass.sync({
       outputStyle: 'expanded',
       precision: 10,
       includePaths: ['.']
-    }).on('error', $.sass.logError))
+    }).on('error', sass.logError))
   <%_ } else { -%>
   return src('app/styles/*.css', {
     sourcemaps: !isProd,