Bump vue from 2.5.20 to 2.5.21 in /apps/updatenotification

Bumps [vue](https://github.com/vuejs/vue) from 2.5.20 to 2.5.21.
- [Release notes](https://github.com/vuejs/vue/releases)
- [Commits](https://github.com/vuejs/vue/compare/v2.5.20...v2.5.21)

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

apps/updatenotification/package-lock.json

@@ -1577,7 +1577,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -1992,7 +1993,8 @@
         "safe-buffer": {
           "version": "5.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -2048,6 +2050,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -2091,12 +2094,14 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },
@@ -4367,9 +4372,9 @@
       }
     },
     "vue": {
-      "version": "2.5.20",
-      "resolved": "https://registry.npmjs.org/vue/-/vue-2.5.20.tgz",
-      "integrity": "sha512-kVLZi8RWOk8qwAt+a0bVDy9VV5Zzcnj0fLCMyKLx1dmEBjqmYJYRWHvPwiypiJBtJkdmROy5NP5hyDqTdfBcvQ=="
+      "version": "2.5.21",
+      "resolved": "https://registry.npmjs.org/vue/-/vue-2.5.21.tgz",
+      "integrity": "sha512-Aejvyyfhn0zjVeLvXd70h4hrE4zZDx1wfZqia6ekkobLmUZ+vNFQer53B4fu0EjWBSiqApxPejzkO1Znt3joxQ=="
     },
     "vue-click-outside": {
       "version": "1.0.7",

apps/updatenotification/package.json

@@ -25,7 +25,7 @@
   "dependencies": {
     "nextcloud-vue": "^0.4.5",
     "v-tooltip": "^2.0.0-rc.33",
-    "vue": "^2.5.20",
+    "vue": "^2.5.21",
     "vue-click-outside": "^1.0.7"
   },
   "devDependencies": {