use electron-builder's static AppImage runtime (#1816)

electron-builder added compatibility with the AppImage Type2 runtime
(i.e. FUSE-less runtime). However, this is - for now anyway - an opt-in
feature, which this commit enables.

electron-builder.yml

@@ -59,6 +59,9 @@ linux:
     icon: assets/icons/icon.png
     artifactName: ${productName}-${os}-${arch}.${ext}
 
+toolsets:
+    appimage: "1.0.2"
+
 npmRebuild: false
 afterAllArtifactBuild: scripts/after-all-artifact-build.mjs
 publish: