happa release v1.57.4

Changes towards supporting cluster creation via app bundles

• UISchema for Azure updated by @marians in https://github.com/giantswarm/happa/pull/4085
• Visual improvements of the schema form added by @gusevda in https://github.com/giantswarm/happa/pull/4040, https://github.com/giantswarm/happa/pull/4053
• Test cases added for schema using subschemas and oneOf, anyOf, not by @marians in https://github.com/giantswarm/happa/pull/4058
• Schema form number field improvements added by @gusevda in https://github.com/giantswarm/happa/pull/4062
• OpenStack schema removed by @kuosandys in https://github.com/giantswarm/happa/pull/4068
• Validation errors improvements in schema form added by @kuosandys in https://github.com/giantswarm/happa/pull/4059
• 2020-12 draft support added by @gusevda in https://github.com/giantswarm/happa/pull/4079
• Removing of empty objects and arrays from form fields while editing added by @kuosandys in https://github.com/giantswarm/happa/pull/4084
• Multi-line string support and long titles/descriptions support added by @kuosandys in https://github.com/giantswarm/happa/pull/4095
• Preprocessing of schema to handle oneOf and anyOf keywords added by @gusevda in https://github.com/giantswarm/happa/pull/4102

Full Changelog: https://github.com/giantswarm/happa/compare/v1.57.3...v1.57.4