Bump nextcloud-server from 0.15.7 to 0.15.9

Bumps [nextcloud-server](https://github.com/ChristophWurst/nextcloud-server) from 0.15.7 to 0.15.9.
- [Release notes](https://github.com/ChristophWurst/nextcloud-server/releases)
- [Commits](https://github.com/ChristophWurst/nextcloud-server/compare/v0.15.7...v0.15.9)

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

package-lock.json

@@ -5750,9 +5750,9 @@
       "integrity": "sha512-5RNNHP8ymxtqOEwirc4n3uv9uAga2V6wUZ7ns7mQrQQtFh/SLEX8ogSsqxquJWZ7+Jc9gVJSeRcRMLoAag966A=="
     },
     "nextcloud-server": {
-      "version": "0.15.7",
-      "resolved": "https://registry.npmjs.org/nextcloud-server/-/nextcloud-server-0.15.7.tgz",
-      "integrity": "sha512-MjARpb8LQdOJCf21gVeHu8HVU41L9lOOfMYjw9p1fDqJxlucKenrvRd0tvnp9OBkpJAuBW/A5/wRBbXXe9+r0Q==",
+      "version": "0.15.9",
+      "resolved": "https://registry.npmjs.org/nextcloud-server/-/nextcloud-server-0.15.9.tgz",
+      "integrity": "sha512-QFgVMMNdUrGtVyRyDb7d6qM9zk7OdwzllBWPdNmwnp9xc9rhZbdXSeP+K0g6vsfT43HBCW1rmSOrDeU39LKOlQ==",
       "requires": {
         "@types/jquery": "^2.0.50"
       }

package.json

@@ -17,7 +17,7 @@
     "@vue/babel-preset-app": "^3.1.1",
     "nextcloud-axios": "^0.1.2",
     "nextcloud-password-confirmation": "^0.4.0",
-    "nextcloud-server": "^0.15.6",
+    "nextcloud-server": "^0.15.9",
     "nextcloud-vue": "^0.4.4",
     "vue": "^2.5.16",
     "vuex": "^3.0.1"