Release v0.4.0

What's Changed

• Improve release docs after our 0.3.1. Plus some more improvements. by @arthurvd in #388
• Fix some minor apidocs by @arthurvd in #390
• Add toplevel hydrolib.core.io.dflowfm tree structure by @tim-vd-aardweg in #392
• Update .gitignore by @tim-vd-aardweg in #404
• Enums are incorrectly written to files by @tim-vd-aardweg in #403
• Use cz cl to add changelog for 0.2.1, 0.3.0 and 0.3.1 by @arthurvd in #389
• #355: Add support for non-recursively loading models by @priscavdsluis in #401
• #308: Change data block default spacing from 4 to 2 by @priscavdsluis in #407
• #370: Suppress warning in polyfile parser that the white space at the start of the line is ignored. by @priscavdsluis in #409
• Refactor the support for vectors in .bc files. by @tim-vd-aardweg in #394
• #258: Move the base module in XYZ to IO (does not belong in dflowfm.xyz) by @priscavdsluis in #418
• Small refactoring of the VectorQuantityUnitPairs and VectorForcingBase by @tim-vd-aardweg in #422
• #308: Improve BC file formatting by @priscavdsluis in #406
• Docs/412 install test notebook for 0.3.1 by @arthurvd in #414
• Update pydantic to the latest version (1.10.2) by @tim-vd-aardweg in #419
• Ensure that QuantityUnitPairs that are not part of a vector are correctly parsed by @tim-vd-aardweg in #420
• Docs/393 create tutorial magdalena by @arthurvd in #431
• #429: Rename variable in generate_nodes function since it causes a crash by @priscavdsluis in #437
• 353: Correct polylinefile validation for Structure and its subclasses by @arthurvd in #416
• Remove io namespace and improve imports by @tim-vd-aardweg in #438
• #395: Add demo for DSD 2022 by @priscavdsluis in #397

Full Changelog: 0.3.1...0.4.0