Orleans v7 upgrade

[htxryan]

Description

Upgrading to Orleans v7 (and .NET 7).

Fixes #36

Type of Change

• Bug fix
• New Feature
• Documentation
• Code improvement
• Breaking change - if a public API changes, or any change that DOES or MAY require a major revision to the NuGet package version due to semver.
• Unit tests
• Code samples
• Added your repository URL to the readme because you make use of this super cool package! ;)
• Other

Describe testing that was performed for your change

All existing tests are passing.

Checklist

• Read the https://github.com/OrleansContrib/Orleans.SyncWork/blob/main/CONTRIBUTING.md
• Ran unit tests and ensured they passed
• Added unit tests where applicable
• Referenced an issue where applicable
• Ran dotnet-format locally

[Kritner]

Sorry about the delay, I'll take a look at this shortly!

[Kritner]

Looks great, thanks @htxryan! I'll get a release out shortly