Bump electron from 20.0.0 to 39.8.5 in /Damselfly.Desktop

Bumps [electron](https://github.com/electron/electron) from 20.0.0 to 39.8.5.
- [Release notes](https://github.com/electron/electron/releases)
- [Commits](electron/electron@v20.0.0...v39.8.5)

---
updated-dependencies:
- dependency-name: electron
  dependency-version: 39.8.5
  dependency-type: direct:development
...

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

Author: dependabot[bot]

Damselfly.Desktop/package.json

@@ -22,7 +22,7 @@
   "author": "Mark Otway",
   "license": "CC0-1.0",
   "devDependencies": {
-    "electron": "20.0.0",
+    "electron": "39.8.5",
     "electron-builder": "23.3.3"
   },
   "build": {