Bump ReportGenerator from 5.3.7 to 5.3.8

Bumps ReportGenerator from 5.3.7 to 5.3.8.

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

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

Author: dependabot[bot]

build/targets/tests/Packages.props

@@ -1,6 +1,6 @@
 <Project>
   <ItemGroup>
-    <PackageVersion Include="ReportGenerator" Version="5.3.7" />
+    <PackageVersion Include="ReportGenerator" Version="5.3.8" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.CodeFix.Testing" Version="1.1.2-beta1.24314.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
     <PackageVersion Include="Verify.Nupkg" Version="1.1.6" />