Bump ParquetSharp dependency to stable 15.0.2.1 release (#20)

Author: adamreeve

ParquetSharp.Dataset/ParquetSharp.Dataset.csproj

@@ -25,7 +25,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="ParquetSharp" Version="15.0.2-beta1" />
+    <PackageReference Include="ParquetSharp" Version="15.0.2.1" />
     <PackageReference Include="Apache.Arrow" Version="15.0.1" />
   </ItemGroup>