Bump gulp-sourcemaps from 2.6.5 to 3.0.0

Bumps [gulp-sourcemaps](https://github.com/gulp-sourcemaps/gulp-sourcemaps) from 2.6.5 to 3.0.0.
- [Release notes](https://github.com/gulp-sourcemaps/gulp-sourcemaps/releases)
- [Commits](https://github.com/gulp-sourcemaps/gulp-sourcemaps/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -38,7 +38,7 @@
     "gulp-mode": "^1.0.2",
     "gulp-postcss": "^8.0.0",
     "gulp-sass": "^4.0.2",
-    "gulp-sourcemaps": "^2.6.5",
+    "gulp-sourcemaps": "^3.0.0",
     "gulp-terser": "^1.4.1",
     "html-webpack-plugin": "^4.5.0",
     "lazypipe": "^1.0.2",