Bump gulp-imagemin from 6.2.0 to 7.1.0

Bumps [gulp-imagemin](https://github.com/sindresorhus/gulp-imagemin) from 6.2.0 to 7.1.0.
- [Release notes](https://github.com/sindresorhus/gulp-imagemin/releases)
- [Commits](sindresorhus/gulp-imagemin@v6.2.0...v7.1.0)

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

package.json

@@ -46,7 +46,7 @@
     "get-twitter-info": "^2.0.2",
     "got": "^10.7.0",
     "gulp": "^4.0.2",
-    "gulp-imagemin": "^6.2.0",
+    "gulp-imagemin": "^7.1.0",
     "gulp-jimp": "^0.1.0",
     "gulp-pug": "4.0.1",
     "gulp-rename": "^2.0.0",