Bump xunit from 2.6.2 to 2.6.3 (#347)

Bumps [xunit](https://github.com/xunit/xunit) from 2.6.2 to 2.6.3.
- [Commits](xunit/xunit@2.6.2...2.6.3)

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

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

src/PublicApiGeneratorTests/PublicApiGeneratorTests.csproj

@@ -25,7 +25,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="xunit" Version="2.6.2" />
+    <PackageReference Include="xunit" Version="2.6.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.5" NoWarn="NU1701">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>