Bump System.Net.Http

Bumps System.Net.Http from 4.1.0 to 4.3.4.

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

ClientLibrary/Quickstarts/dotnet/MaterializeUserQuickStarts/packages.config

@@ -15,7 +15,7 @@
   <package id="System.IdentityModel.Tokens.Jwt" version="5.2.0-preview2-41113220915" targetFramework="net461" />
   <package id="System.IO" version="4.1.0" targetFramework="net461" />
   <package id="System.Linq" version="4.1.0" targetFramework="net461" />
-  <package id="System.Net.Http" version="4.1.0" targetFramework="net461" />
+  <package id="System.Net.Http" version="4.3.4" targetFramework="net461" />
   <package id="System.Net.Primitives" version="4.0.11" targetFramework="net461" />
   <package id="System.Reflection" version="4.1.0" targetFramework="net461" />
   <package id="System.Reflection.Extensions" version="4.0.1" targetFramework="net461" />