v5.0.0

• #105 - README link fix (@SimonCropp)
• #109 - additional JSON configuration example (@mason-mcglothlin)
• #112 - package repository URL update (@MaximRouiller)
• #124 - add netstandard2.0 target (@nblumhardt)
• #120 - README updates (@nblumhardt)
• #132 - general code refreshments (@nblumhardt)
• #133 - drop support for legacy "raw" payload format/Seq 3.2 and earlier (@nblumhardt)
• #145 - update to the .NET 5 SDK, add net5.0 target (@nblumhardt)