Bump System.Net.Http from 4.3.0 to 4.3.4 in /src/Serilog.Sinks.Splunk

Bumps System.Net.Http from 4.3.0 to 4.3.4.

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

Author: dependabot[bot]

src/Serilog.Sinks.Splunk/Serilog.Sinks.Splunk.csproj

@@ -37,7 +37,7 @@
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard1.1' ">
-    <PackageReference Include="System.Net.Http" Version="4.3.0" />
+    <PackageReference Include="System.Net.Http" Version="4.3.4" />
   </ItemGroup>
 
   <ItemGroup>