Middleware does not work without the static Serilog.Log

[pnmcosta]

Description
Middleware relies on the static Serilog.Log instead of the one defined with the extension method UseSerilog.

Reproduction
Set UseSerilog with your own static logger, the middleware does not emit any event logs.

Expected behavior
I would hope the middleware would use the same logger set wtih UseSerilog, otherwise, please extend RequestLoggingOptions so that we can also define there what logger should be used to create the context for the middleware.

Relevant package, tooling and runtime versions
<PackageReference Include="Serilog.AspNetCore" Version="3.2.0" />

Additional context
With your guidance, I'd happily do a PR for this.

[pnmcosta]

Offending line: https://github.com/serilog/serilog-aspnetcore/blob/dev/src/Serilog.AspNetCore/AspNetCore/RequestLoggingMiddleware.cs#L76

[pnmcosta]

Duplicate of: #182