Release v0.4.0

[mx-moth]

Overview ticket for tracking things that need doing for the v0.4.0 release

• [x] #55
  • [x] #56
  • [x] Also update in conda-forge
• [x] #37
  • [x] #38
• [x] #54
  • [x] #58
• [x] Release the package on PyPI
• [x] Release the package on conda-forge
• [x] Update CSIRO Data Access Portal
• [x] Publish emsarray-smc v0.2.0 csiro-coasts/emsarray-smc#1

[mx-moth]

emsarray has been published on the DAP, and has a permalink / Handle of http://hdl.handle.net/102.100.100/482171?index=1