Bump Plotly.NET and Plotly.NET.ImageExport

Bumps [Plotly.NET](https://github.com/plotly/Plotly.NET) and [Plotly.NET.ImageExport](https://github.com/plotly/Plotly.NET). These dependencies needed to be updated together.

Updates `Plotly.NET` from 4.2.0 to 5.0.0
- [Release notes](https://github.com/plotly/Plotly.NET/releases)
- [Changelog](https://github.com/plotly/Plotly.NET/blob/dev/RELEASE_NOTES.md)
- [Commits](plotly/Plotly.NET@4.2.0...5.0.0)

Updates `Plotly.NET.ImageExport` from 5.0.1 to 6.1.0
- [Release notes](https://github.com/plotly/Plotly.NET/releases)
- [Changelog](https://github.com/plotly/Plotly.NET/blob/dev/RELEASE_NOTES.md)
- [Commits](https://github.com/plotly/Plotly.NET/commits)

---
updated-dependencies:
- dependency-name: Plotly.NET
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: Plotly.NET.ImageExport
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

BitFaster.Caching.HitRateAnalysis/BitFaster.Caching.HitRateAnalysis.csproj

@@ -30,7 +30,7 @@
     <PackageReference Include="MathNet.Numerics" Version="5.0.0" />
       <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="9.0.0" />
       <PackageReference Include="Plotly.NET.CSharp" Version="0.11.1" />
-      <PackageReference Include="Plotly.NET.ImageExport" Version="5.0.1" />
+      <PackageReference Include="Plotly.NET.ImageExport" Version="6.1.0" />
   </ItemGroup>
 
   <ItemGroup>

BitFaster.Caching.ThroughputAnalysis/BitFaster.Caching.ThroughputAnalysis.csproj

@@ -27,8 +27,8 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="9.0.0" />
-    <PackageReference Include="Plotly.NET" Version="4.2.0" />
-    <PackageReference Include="Plotly.NET.ImageExport" Version="5.0.1" />
+    <PackageReference Include="Plotly.NET" Version="5.0.0" />
+    <PackageReference Include="Plotly.NET.ImageExport" Version="6.1.0" />
   </ItemGroup>
 
   <ItemGroup>