Bump @vue/cli-plugin-pwa from 4.5.14 to 4.5.15 in /frontend

Bumps [@vue/cli-plugin-pwa](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-plugin-pwa) from 4.5.14 to 4.5.15.
- [Release notes](https://github.com/vuejs/vue-cli/releases)
- [Changelog](https://github.com/vuejs/vue-cli/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vue-cli/commits/v4.5.15/packages/@vue/cli-plugin-pwa)

---
updated-dependencies:
- dependency-name: "@vue/cli-plugin-pwa"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

frontend/package.json

@@ -21,7 +21,7 @@
   "devDependencies": {
     "@vue/cli-plugin-babel": "~4.5.14",
     "@vue/cli-plugin-eslint": "~4.5.15",
-    "@vue/cli-plugin-pwa": "~4.5.14",
+    "@vue/cli-plugin-pwa": "~4.5.15",
     "@vue/cli-plugin-router": "~4.5.15",
     "@vue/cli-service": "~4.5.14",
     "babel-eslint": "^10.1.0",

frontend/yarn.lock

@@ -1415,12 +1415,12 @@
     webpack "^4.0.0"
     yorkie "^2.0.0"
 
-"@vue/cli-plugin-pwa@~4.5.14":
-  version "4.5.14"
-  resolved "https://registry.yarnpkg.com/@vue/cli-plugin-pwa/-/cli-plugin-pwa-4.5.14.tgz#55f58689f33109dfc001f45028c123c1097c66d3"
-  integrity sha512-Ikg2+IHSXGf+KFNkDbKDkm0HZOFBMQWVrIv8yipmOG1q7qbYmRF1rrYLvttLZlGa7/P8J8Zv3uFnGxWlmdeJYA==
+"@vue/cli-plugin-pwa@~4.5.15":
+  version "4.5.15"
+  resolved "https://registry.yarnpkg.com/@vue/cli-plugin-pwa/-/cli-plugin-pwa-4.5.15.tgz#eb800c418d96b496deec9d063a1798fe6e9c2db8"
+  integrity sha512-yQzsspaIkjeQyN6btF8ATgbJFU023q1HC8uUpmiBa4QE9EyBlR8fSrKFhcJ0EmT6KnU7PMwlnOJ/OqjguFnufA==
   dependencies:
-    "@vue/cli-shared-utils" "^4.5.14"
+    "@vue/cli-shared-utils" "^4.5.15"
     webpack "^4.0.0"
     workbox-webpack-plugin "^4.3.1"