MINOR: [C#] Bump ZstdSharp.Port from 0.8.4 to 0.8.5 in /csharp

Bumps [ZstdSharp.Port](https://github.com/oleg-st/ZstdSharp) from 0.8.4 to 0.8.5.
- [Release notes](https://github.com/oleg-st/ZstdSharp/releases)
- [Commits](oleg-st/ZstdSharp@0.8.4...0.8.5)

---
updated-dependencies:
- dependency-name: ZstdSharp.Port
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

csharp/src/Apache.Arrow.Compression/Apache.Arrow.Compression.csproj

@@ -13,7 +13,7 @@
 
   <ItemGroup>
     <PackageReference Include="K4os.Compression.LZ4.Streams" Version="1.3.8" />
-    <PackageReference Include="ZstdSharp.Port" Version="0.8.4" />
+    <PackageReference Include="ZstdSharp.Port" Version="0.8.5" />
   </ItemGroup>
 
   <ItemGroup>