Bump MongoDB.Driver from 2.15.0 to 2.19.0 in /src/YumeChan.Core

Bumps [MongoDB.Driver](https://github.com/mongodb/mongo-csharp-driver) from 2.15.0 to 2.19.0.
- [Release notes](https://github.com/mongodb/mongo-csharp-driver/releases)
- [Commits](mongodb/mongo-csharp-driver@v2.15.0...v2.19.0)

---
updated-dependencies:
- dependency-name: MongoDB.Driver
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

src/YumeChan.Core/YumeChan.Core.csproj

@@ -35,7 +35,7 @@
  <PackageReference Include="Microsoft.Extensions.FileProviders.Physical" Version="6.0.0" />
  <PackageReference Include="Microsoft.Extensions.Http" Version="6.0.0" />
  <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0" />
- <PackageReference Include="MongoDB.Driver" Version="2.15.0" />
+ <PackageReference Include="MongoDB.Driver" Version="2.19.0" />
  <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="6.0.4" />
  <PackageReference Include="NuGet.Configuration" Version="6.1.0" />
  <PackageReference Include="NuGet.Protocol" Version="6.1.0" />