OSX: Compress DMG

[jflyper]

UDB0 is good enough.

[basdelfos]

Oddly enough when I created the dmg locally it already compressed the dmg to 89MB, probably an overall systemsetting that already enabled some kind of compression.
I tested your PR to compress with UDB0 and now the filesize reduced to 80MB. Everything is working fine.

[mikeller]

Weird, according to https://github.com/LinusU/node-appdmg#specification it looks like format should go inside specification (and the same applies to background, maybe that's why the background is not working, @basdelfos).

[basdelfos]

Doh, that's it. Now I remember that the background was working in the beginning when I used a separate json file.

[basdelfos]

@jflyper can you replace this from line 114:

    return gulp.src([])
        .pipe(appdmg({
            target: path.join(releaseDir, get_release_filename('macOS', 'dmg')),
            basepath: path.join(appsDir, pkg.name, 'osx64'),
            specification: {
                title: 'Betaflight Configurator',
                contents: [
                    { 'x': 448, 'y': 342, 'type': 'link', 'path': '/Applications' },
                    { 'x': 192, 'y': 344, 'type': 'file', 'path': pkg.name + '.app', 'name': 'Betaflight Configurator.app' }
                ],
                background: path.join(__dirname, 'images/dmg-background.png'),
                format: 'UDZO',
                window: {
                    size: {
                        width: 638,
                        height: 479
                    }
                }
            },
        })
    );

It fixes the compression to move to specification and the correct enum value. Also fixes the background not showing in the dmg.

[jflyper]

Strange. The dmg file is 205MB, and still no background image...

[jflyper]

Tags should be double-quoted? Not mandatory???

[basdelfos]

Quoting is not mandatory as long as the name does not have special characters like spaces, dashes, ...