Release v0.4.0

This release introduces a way to append multiple/nested elements.
✅ No breaking changes.

Example:

const svg = new Svg();
svg.appendChild([
    RawElement.create('a', {}, [
        RawElement.create('b', {}, [
            node.text({}, [
                node.tspan({}, 'Lorem'),
                node.tspan({}, 'ipsum'),
            ]),
            'raw text',
            'another raw text',
        ]),
        RawElement.create('some-other-element'),
    ]),
]);

Full Changelog: v0.3.0...v0.4.0