chore: dependency updates (#1341)

* chore: dependency updates

- ensure correct webui is used (clean before each build)
- switch to latest electron and electron-builder
  (CI uses npm ci due to package-lock.json)
  - latest electron-builder includes fixes needed for notariztion of mac artifact
    (#1211)
- switch to future-proof multiaddr-to-uri
- fix CI: cache downloaded electron and electron-builder artifacts

.travis.yml

@@ -12,6 +12,15 @@ os:
 
 osx_image: xcode11
 
+cache:
+  directories:
+    - $HOME/.npm
+    - $HOME/.cache/electron
+    - $HOME/.cache/electron-builder
+
+before_cache:
+  - rm -rf $HOME/.cache/electron-builder/wine
+
 before_script:
   - |
     if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then