Tagged release v0.4.0

f9b8ae1 Fixed tests for items list validation
e401890 Fixes procedure items list require to be not empty
528a1d1 Updated qualification state according to latest specs
dfa3bb6 Check how we work with time from spec (timezone)
56cf32a Implement ownership for questions
a15e843 Fix internal server error occurs when countryName isn't correct. Fixes #107
429220c Add required field valueAddedTaxIncluded to Value. Fixes #116
e1680b8 Periods marked as readonly. Fixes #115, #106
89dd1a3 Move retry function in error module cause of circular imports
82dfc0b Add middleware to cath concurrency errors, and handle them
c89aa91 Add exponential sleep on retry
c55dd05 Change procedure data fields to required. Fixes #112, #108
4ca29fc Add data.procuringEntity.kind field. Fixes #111
3024eba Rename contractPoint field to contactPoint. Fixes #109
91ac102 Move all datetime  model fields to utcdatetime type
04fe851 Fix auctionUrl displaying
7fe003b Fixed #86 when award is cancelled quota returned to remaining quota pool
4f20125 Update tests according to changes
851bc56 Change success response status