update the dependency version

Author: pengli

PayPalCheckoutSdk/PayPalCheckoutSdk.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BraintreeHttp-Dotnet" Version="0.1.5" />
+    <PackageReference Include="BraintreeHttp-Dotnet" Version="0.3.0" />
   </ItemGroup>
 
 </Project>