Bump electron from 6.0.11 to 6.0.12 in /app

Bumps [electron](https://github.com/electron/electron) from 6.0.11 to 6.0.12.
- [Release notes](https://github.com/electron/electron/releases)
- [Commits](https://github.com/electron/electron/compare/v6.0.11...v6.0.12)

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

app/package.json

@@ -66,7 +66,7 @@
     "itunes-nowplaying-mac": "kPherox/itunes-nowplaying-mac#get-artworks-base64"
   },
   "devDependencies": {
-    "electron": "^6.0.11",
+    "electron": "^6.0.12",
     "electron-builder": "^21.1.5",
     "electron-rebuild": "^1.8.6",
     "readline-sync": "1.4.10"

app/yarn.lock

@@ -932,10 +932,10 @@ electron-rebuild@^1.8.6:
     spawn-rx "^3.0.0"
     yargs "^13.2.4"
 
-electron@^6.0.11:
-  version "6.0.11"
-  resolved "https://registry.yarnpkg.com/electron/-/electron-6.0.11.tgz#64effa71397045779a1ddbf51312a41ccf26f491"
-  integrity sha512-mi1oHmeFIQrg+CDQ6lbugZAloOxuWPm/ecEKYe1230PGlDoWND7SYStiWQ2eI4YXAEOL/NvuY88ogemu1qhdBg==
+electron@^6.0.12:
+  version "6.0.12"
+  resolved "https://registry.yarnpkg.com/electron/-/electron-6.0.12.tgz#85bf0061e32f660256cfde95488f1cb75253bc94"
+  integrity sha512-70ODZa1RP6K0gE9IV9YLCXPSyhLjXksCuYSSPb3MljbfwfHo5uE6X0CGxzm+54YuPdE2e7EPnWZxOOsJYrS5iQ==
   dependencies:
     "@types/node" "^10.12.18"
     electron-download "^4.1.0"