Bump the tests group with 2 updates

Bumps the tests group with 2 updates: [xunit](https://github.com/xunit/xunit) and [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit).


Updates `xunit` from 2.5.0 to 2.6.1
- [Commits](xunit/xunit@2.5.0...2.6.1)

Updates `xunit.runner.visualstudio` from 2.5.0 to 2.5.3
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.5.0...2.5.3)

---
updated-dependencies:
- dependency-name: xunit
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: tests
- dependency-name: xunit.runner.visualstudio
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: tests
...

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

src/RxFree.SourceTests.Legacy/RxFree.SourceTests.Legacy.csproj

@@ -15,8 +15,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="xunit" Version="2.5.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
+    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
   </ItemGroup>
 
   <Import Project="..\RxFree\build\RxFree.targets" />

src/RxFree.SourceTests.Nullable/RxFree.SourceTests.Nullable.csproj

@@ -15,8 +15,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="xunit" Version="2.5.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
+    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
   </ItemGroup>
 
   <Import Project="..\RxFree\build\RxFree.targets" />

src/RxFree.SourceTests/RxFree.SourceTests.csproj

@@ -16,8 +16,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="xunit" Version="2.5.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
+    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
   </ItemGroup>
 
   <Import Project="..\RxFree\build\RxFree.targets" />

src/RxFree.Tests/RxFree.Tests.csproj

@@ -6,8 +6,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="xunit" Version="2.5.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
+    <PackageReference Include="xunit" Version="2.6.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
   </ItemGroup>
 
   <ItemGroup>