fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-BRACEEXPANSION-9789073

Author: snyk-bot

package.json

@@ -11,7 +11,7 @@
         "babel-preset-env": "^1.7.0",
         "can-autoplay": "^3.0.0",
         "chart.js": "^2.9.4",
-        "copy-webpack-plugin": "^4.5.1",
+        "copy-webpack-plugin": "^7.0.0",
         "css-loader": "^0.28.11",
         "dayjs": "^1.8.14",
         "debounce": "^1.1.0",
@@ -27,7 +27,7 @@
         "nosleep.js": "^0.7.0",
         "nunjucks": "2.5.2",
         "postcss": "^7.0.17",
-        "postcss-cli": "^5.0.0",
+        "postcss-cli": "^7.1.1",
         "postcss-loader": "^2.1.5",
         "pretty-bytes": "^5.5.0",
         "sass-loader": "^7.0.1",