Electron 9, Fixed breaking changes from 7 and 8.

Fixed file selectors not behaving properly due to breaking change in Electron 7 (#67).
Renamed shell.openItem to shell.openPath (Electron 9 breaking change).

Resolves #67.

package-lock.json

@@ -953,9 +953,9 @@
       }
     },
     "electron": {
-      "version": "8.3.0",
-      "resolved": "https://registry.npmjs.org/electron/-/electron-8.3.0.tgz",
-      "integrity": "sha512-XRjiIJICZCgUr2vKSUI2PTkfP0gPFqCtqJUaTJSfCTuE3nTrxBKOUNeRMuCzEqspKkpFQU3SB3MdbMSHmZARlQ==",
+      "version": "9.0.0",
+      "resolved": "https://registry.npmjs.org/electron/-/electron-9.0.0.tgz",
+      "integrity": "sha512-JsaSQNPh+XDYkLj8APtVKTtvpb86KIG57W5OOss4TNrn8L3isC9LsCITwfnVmGIXHhvX6oY/weCtN5hAAytjVg==",
       "dev": true,
       "requires": {
         "@electron/get": "^1.0.1",