Run build job on Linux

Summary:
This works now with the Electron update. Wine doesn't work there so the app signing step needs to be disabled. I'm not entirely sure if this has other consequences than disabling signing - which we don't use.

We also can't build `.dmg`s on Linux because it relies on a CLI tool that only exists on Macs. But we can quite easily move this to GitHub Actions, which I set up with https://github.com/facebook/flipper/pull/852

Reviewed By: nikoant

Differential Revision: D20160545

fbshipit-source-id: a888c8b0e8f7dbe8bec818d57f5f22bcf800322c

scripts/build-release.ts

@@ -67,7 +67,11 @@ async function buildDist(buildFolder: string) {
   const postBuildCallbacks: (() => void)[] = [];
 
   if (process.argv.indexOf('--mac') > -1) {
-    targetsRaw.push(Platform.MAC.createTarget(['dir', 'dmg']));
+    targetsRaw.push(Platform.MAC.createTarget(['dir']));
+    // You can build mac apps on Linux but can't build dmgs, so we separate those.
+    if (process.argv.indexOf('--mac-dmg') > -1) {
+      targetsRaw.push(Platform.MAC.createTarget(['dmg']));
+    }
     postBuildCallbacks.push(() =>
       spawn('zip', ['-qyr9', '../Flipper-mac.zip', 'Flipper.app'], {
         cwd: path.join(__dirname, '..', 'dist', 'mac'),
@@ -108,6 +112,9 @@ async function buildDist(buildFolder: string) {
         },
         electronDownload: electronDownloadOptions,
         npmRebuild: false,
+        win: {
+         signAndEditExecutable: false
+        }
       },
       projectDir: buildFolder,
       targets,