Bump NUnit3TestAdapter from 6.3.0 to 6.3.1 (#104)

---
updated-dependencies:
- dependency-name: NUnit3TestAdapter
  dependency-version: 6.3.1
  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>

Author: dependabot[bot]

MimeTypes.Tests/MimeTypes.Tests.csproj

@@ -12,7 +12,7 @@
 
     <ItemGroup>
         <PackageReference Include="NUnit" Version="5.0.0" />
-        <PackageReference Include="NUnit3TestAdapter" Version="6.3.0" />
+        <PackageReference Include="NUnit3TestAdapter" Version="6.3.1" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
     </ItemGroup>