Bump gulp-imagemin from 7.1.0 to 9.1.0 (#5052)

Author: dependabot[bot]

{{cookiecutter.project_slug}}/package.json

@@ -14,7 +14,7 @@
     "concurrently": "^9.0.0",
     "cssnano": "^7.0.0",
     "gulp": "^5.0.0",
-    "gulp-imagemin": "^7.1.0",
+    "gulp-imagemin": "^9.1.0",
     "gulp-plumber": "^1.2.1",
     "gulp-postcss": "^10.0.0",
     "gulp-rename": "^2.0.0",