Remove semver ranges from dev dependencies to keep them consistent with others

Author: przemyslawzalewski

examples/package.json

@@ -32,7 +32,7 @@
     "@babel/plugin-proposal-class-properties": "7.8.3",
     "@babel/preset-env": "7.8.3",
     "@babel/preset-react": "7.8.3",
-    "autoprefixer": "^9.7.4",
+    "autoprefixer": "9.7.4",
     "babel-eslint": "10.0.3",
     "babel-loader": "8.0.6",
     "css-loader": "3.4.2",
@@ -43,7 +43,7 @@
     "eslint-plugin-react-hooks": "2.3.0",
     "gh-pages": "2.2.0",
     "html-webpack-plugin": "3.2.0",
-    "postcss-loader": "^3.0.0",
+    "postcss-loader": "3.0.0",
     "prettier": "1.19.1",
     "style-loader": "1.1.3",
     "stylelint": "13.0.0",