fix: spec/fixtures/dynamic_finders/plugin_version/materializer/compos…

…er_file/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-BRACES-6838727
- https://snyk.io/vuln/SNYK-JS-MICROMATCH-6838728

spec/fixtures/dynamic_finders/plugin_version/materializer/composer_file/package.json

@@ -27,6 +27,6 @@
         "sass-loader": "^1.0.2",
         "style-loader": "^0.8.3",
         "url-loader": "0.5.6",
-        "webpack": "^1.9.8"
+        "webpack": "^2.2.0"
     }
 }