Bump AutoFixture from 4.17.0 to 4.18.0 in /backend

Bumps [AutoFixture](https://github.com/AutoFixture/AutoFixture) from 4.17.0 to 4.18.0.
- [Release notes](https://github.com/AutoFixture/AutoFixture/releases)
- [Commits](AutoFixture/AutoFixture@v4.17.0...v4.18.0)

---
updated-dependencies:
- dependency-name: AutoFixture
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/RossyntBackendIntegrationTest/RossyntBackendIntegrationTest.csproj

@@ -9,7 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="AutoFixture" Version="4.17.0" />
+        <PackageReference Include="AutoFixture" Version="4.18.0" />
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="6.0.13" Condition="'$(TargetFramework)' == 'net6.0'" />
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="7.0.2" Condition="'$(TargetFramework)' == 'net7.0'" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.1" />

backend/RossyntBackendUnitTest/RossyntBackendUnitTest.csproj

@@ -9,7 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="AutoFixture" Version="4.17.0" />
+        <PackageReference Include="AutoFixture" Version="4.18.0" />
         <PackageReference Include="NUnit" Version="3.13.3" />
         <PackageReference Include="NUnit3TestAdapter" Version="4.3.1" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.1" />