Bump log4net from 3.3.0 to 3.3.1

---
updated-dependencies:
- dependency-name: log4net
  dependency-version: 3.3.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/Platforms/Exceptionless.Log4net/Exceptionless.Log4net.csproj

@@ -25,7 +25,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Package References">
-    <PackageReference Include="log4net" Version="3.3.0" />
+    <PackageReference Include="log4net" Version="3.3.1" />
   </ItemGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' " Label="Build">