v4.0.0

Breaking Changes

• Dropped official support for .NET 6/7 and removed testing targets.
• Added .NET 9 target and relevant dependencies

Misc

• Bumped Microsoft.Extensions.Caching.Memory to resolve CVE warnings.
• Bumped ZiggyCreatures.FusionCache to 1.4.1
• Bumped Auth0.* packages to 7.29.0