Automated adding of index.min.css.map in gulp on npm build

gulpfile.js

 const gulp = require('gulp');
 const compile = require('gulp-postcss');
-const maps = require('gulp-sourcemaps');
-const rename = require('gulp-rename');
+const sourcemaps = require('gulp-sourcemaps');
 const clean = require('gulp-clean-css');
+const rename = require('gulp-rename');
+const filter = require('gulp-filter');
 
 gulp.task('build', () =>
-    gulp.src('src/index.css').
-        pipe(maps.init()).
-          pipe(compile()).
-        pipe(maps.write('.')).
-        pipe(gulp.dest('dist')).
-        pipe(clean()).
-        pipe(rename('index.min.css')).
-        pipe(gulp.dest('dist')),
-);
\ No newline at end of file
+    gulp.src('src/index.css')
+      .pipe(sourcemaps.init())
+        .pipe(compile())
+      .pipe(sourcemaps.write('.'))
+      .pipe(gulp.dest('dist'))
+      
+      .pipe(filter('**/*.css'))
+      .pipe(clean())
+      .pipe(rename({suffix:'.min'}))
+      .pipe(sourcemaps.write('.'))
+      .pipe(gulp.dest("dist")),
+);

package.json

@@ -12,6 +12,7 @@
     "gulp": "^4.0.2",
     "gulp-clean-css": "^4.3.0",
     "gulp-concat-css": "^3.1.0",
+    "gulp-filter": "^6.0.0",
     "gulp-postcss": "^8.0.0",
     "gulp-rename": "^2.0.0",
     "gulp-sourcemaps": "^2.6.5",
@@ -21,8 +22,8 @@
   },
   "peerDependencies": {
     "autoprefixer": "^9.4.5",
-    "postcss-nested": "^4.1.1",
-    "postcss": "^7.0.0"
+    "postcss": "^7.0.0",
+    "postcss-nested": "^4.1.1"
   },
   "repository": {
     "type": "git",