2 new commits pushed to

<https://github.com/pact-foundation/pact-net/tree/master|master>

by adamrodger

<https://github.com/pact-foundation/pact-net/commit/51a0a02bafd73b533e6b956adff8761075914c50|51a0a02b>

- refactor!: Remove obsolete IMessagePact and MessagePact

<https://github.com/pact-foundation/pact-net/commit/d621342cf78b25ad07f9c33b9cd396dcce2a5163|d621342c>

- docs: Link to and update 5.x upgrade guide pact-foundation/pact-net