Bump coverlet.collector from 6.0.3 to 6.0.4

---
updated-dependencies:
- dependency-name: coverlet.collector
  dependency-version: 6.0.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: coverlet.collector
  dependency-version: 6.0.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/Avalonia.Samples/Testing/TestableApp.Headless.XUnit/TestableApp.Headless.XUnit.csproj

@@ -17,7 +17,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="6.0.3">
+    <PackageReference Include="coverlet.collector" Version="6.0.4">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>