remove unused gulp-purifycss dep

Author: jonchurch

gulpfile.js

@@ -18,7 +18,6 @@ const cssnano = require('gulp-cssnano')
 const htmlmin = require('gulp-htmlmin')
 const imagemin = require('gulp-imagemin')
 const jsonmin = require('gulp-jsonmin')
-const purify = require('gulp-purifycss')
 const purgeCss = require('gulp-purgecss')
 // const responsive = require('gulp-responsive') // Disabled: old Sharp version incompatible with Node 22
 const terser = require('gulp-terser')