Bump electron-updater from 6.1.8 to 6.3.0 in /client/electron

Bumps [electron-updater](https://github.com/electron-userland/electron-builder/tree/HEAD/packages/electron-updater) from 6.1.8 to 6.3.0.
- [Release notes](https://github.com/electron-userland/electron-builder/releases)
- [Changelog](https://github.com/electron-userland/electron-builder/blob/master/packages/electron-updater/CHANGELOG.md)
- [Commits](https://github.com/electron-userland/electron-builder/commits/electron-updater@6.3.0/packages/electron-updater)

---
updated-dependencies:
- dependency-name: electron-updater
  dependency-type: direct:production
...

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

client/electron/package.json

@@ -29,7 +29,7 @@
         "electron-log": "^5.1.2",
         "electron-serve": "~1.3.0",
         "electron-unhandled": "~4.0.1",
-        "electron-updater": "6.1.8",
+        "electron-updater": "6.3.0",
         "electron-window-state": "~5.0.3",
         "regedit": "^5.1.3"
     },