v5.0.0

• #134 - optimize TimestampTokenRenderer (@sungam3r)
• #135 - added tests (@sungam3r)
• #137 - support upper and lower-case formatting for all level widths (@nblumhardt)
• #142 - API approval tests (@sungam3r)
• #141 - auditing support (@sungam3r)
• #146 - support TraceId and SpanId placeholders, update to Serilog 3.1 (@nblumhardt)