⚡ Nuke package-lock; update dev dependencies

Includes replacement of styling with stylelint and a plugin for stylus. Pug and stylus code got a bit refactored due to the addition of new rules.

.stylelintrc

@@ -0,0 +1,37 @@
+plugins:
+    - stylelint-stylus
+overrides:
+    -   files:
+        -   '*.stylus'
+        -   '*.styl'
+        -   '**/*.stylus'
+        -   '**/*.styl'
+        customSyntax: 'postcss-styl'
+rules:
+    color-no-invalid-hex: true
+    font-family-no-duplicate-names: true
+    named-grid-areas-no-invalid: true
+    function-calc-no-unspaced-operator: true
+    function-linear-gradient-no-nonstandard-direction: true
+    string-no-newline: true
+    unit-no-unknown: true
+    keyframe-declaration-no-important: true
+    keyframe-block-no-duplicate-selectors: true
+    declaration-block-no-duplicate-properties: true
+    declaration-block-no-shorthand-property-overrides: true
+    declaration-block-no-duplicate-custom-properties: true
+    block-no-empty: true
+    media-feature-name-no-unknown: true
+    comment-no-empty: true
+    no-duplicate-at-import-rules: true
+    no-empty-source: true
+    alpha-value-notation: 'number'
+    length-zero-no-unit: true
+    declaration-block-single-line-max-declarations: 1
+    selector-attribute-quotes: always
+    selector-id-pattern: 'the[A-Z][a-zA-Z]*'
+    no-irregular-whitespace: true
+
+    stylus/pythonic: 'always'
+    stylus/semicolon: 'never'
+    stylus/property-no-unknown: true

app/package.json

@@ -62,7 +62,7 @@
     "electron-packager": "^15.0.0",
     "execa": "^5.1.1",
     "extract-zip": "^2.0.1",
-    "fs-extra": "^9.0.1",
+    "fs-extra": "^10.1.0",
     "fuse.js": "^3.6.1",
     "google-closure-compiler": "^20191111.0.0",
     "highlight.js": "^10.4.1",

gulpfile.js

@@ -269,13 +269,20 @@ const watch = () => {
 };
 
 const lintStylus = () => {
-    const stylint = require('gulp-stylint');
-    return gulp.src(['./src/styl/**/*.styl', '!./src/styl/3rdParty/**/*.styl'])
-    .pipe(stylint())
-    .pipe(stylint.reporter())
-    .pipe(stylint.reporter('fail', {
-        failOnWarning: true
-    }));
+    const stylelint = require('stylelint');
+    return stylelint.lint({
+        files: [
+            './src/styl/**/*.styl',
+            '!./src/styl/3rdParty/**/*.styl'
+        ],
+        formatter: 'string'
+    }).then(lintResults => {
+        if (lintResults.errored) {
+            console.log(lintResults.output);
+        } else {
+            console.log('✔ Cheff\'s kiss! 😙👌');
+        }
+    });
 };
 
 const lintJS = () => {