build(deps): bump NLog from 5.1.1 to 5.1.2 in /src (#991)

Bumps [NLog](https://github.com/NLog/NLog) from 5.1.1 to 5.1.2.
- [Release notes](https://github.com/NLog/NLog/releases)
- [Changelog](https://github.com/NLog/NLog/blob/dev/CHANGELOG.md)
- [Commits](NLog/NLog@v5.1.1...v5.1.2)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Splat.NLog/Splat.NLog.csproj

@@ -11,7 +11,7 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="NLog" Version="5.1.1" />
+    <PackageReference Include="NLog" Version="5.1.2" />
     <PackageReference Include="System.Collections.Immutable" Version="7.0.0" />
   </ItemGroup>
   <ItemGroup>