Don't run postcss for `dist/css/*.min.css` files. (#24676)

package.json

@@ -25,7 +25,7 @@
     "css-compile-docs": "node-sass --output-style expanded --source-map true --source-map-contents true --precision 6 assets/scss/docs.scss assets/css/docs.min.css",
     "css-lint": "stylelint --config build/.stylelintrc --syntax scss \"scss/**/*.scss\"",
     "css-lint-docs": "stylelint --config build/.stylelintrc --syntax scss \"assets/scss/*.scss\" && stylelint --config docs/4.0/examples/.stylelintrc \"docs/**/*.css\"",
-    "css-prefix": "postcss --config build/postcss.config.js --replace \"dist/css/*.css\"",
+    "css-prefix": "postcss --config build/postcss.config.js --replace \"dist/css/*.css\" \"!dist/css/*.min.css\"",
     "css-prefix-docs": "postcss --config build/postcss.config.js --replace \"assets/css/docs.min.css\" \"docs/**/*.css\"",
     "css-minify": "cleancss --level 1 --source-map --source-map-inline-sources --output dist/css/bootstrap.min.css dist/css/bootstrap.css && cleancss --level 1 --source-map --source-map-inline-sources --output dist/css/bootstrap-grid.min.css dist/css/bootstrap-grid.css && cleancss --level 1 --source-map --source-map-inline-sources --output dist/css/bootstrap-reboot.min.css dist/css/bootstrap-reboot.css",
     "css-minify-docs": "cleancss --level 1 --source-map --source-map-inline-sources --output assets/css/docs.min.css assets/css/docs.min.css",