D2 bumpup to version 0.6.0, add themes, add options

[vfosnar]

No description provided.

[ggrossetie]

Thanks!
Could you please add a test case for each options added (in the following file):

kroki/ci/tests/smoke.js

Lines 42 to 44 in e9ef670

	{ engine: 'd2', file: 'connections.d2', options: {}, outputFormat: ['svg'] },
	{ engine: 'd2', file: 'connections.d2', options: { layout: 'elk' }, outputFormat: ['svg'] },
	{ engine: 'd2', file: 'connections.d2', options: { sketch: 'true' }, outputFormat: ['svg'] },

[vfosnar]

Alright, tests passed!

[ggrossetie]

All good, thank you 🤗