correct symbols pkg ext (#78)

Author: bitfaster

BitFaster.Caching/BitFaster.Caching.csproj

@@ -19,6 +19,7 @@
     <IncludeSource>True</IncludeSource>
     <IncludeSymbols>True</IncludeSymbols>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
+    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
     <AssemblyVersion>1.0.4.0</AssemblyVersion>
     <FileVersion>1.0.4.0</FileVersion>
   </PropertyGroup>