Bump NUnit from 3.14.0 to 4.4.0

---
updated-dependencies:
- dependency-name: NUnit
  dependency-version: 4.4.0
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: NUnit
  dependency-version: 4.4.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

EchoTcpServerTests/EchoTcpServerTests.csproj

@@ -18,7 +18,7 @@
     <PackageReference Include="JunitXml.TestLogger" Version="7.0.2" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.4.0" />
     <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
   </ItemGroup>

NetSdrClientAppTests/NetSdrClientAppTests.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageReference Include="Moq" Version="4.20.72" />
     <PackageReference Include="NetArchTest.Rules" Version="1.3.2" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.4.0" />
     <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
   </ItemGroup>