[Bugfix] Finalize diagnostics even when an error is thrown (#187)

Author: czechboy0

Sources/swift-openapi-generator/GenerateOptions+runGenerator.swift

@@ -78,11 +78,15 @@ extension _GenerateOptions {
                 isDryRun: isDryRun,
                 diagnostics: diagnostics
             )
+            try finalizeDiagnostics()
         } catch let error as Diagnostic {
             // Emit our nice Diagnostics message instead of relying on ArgumentParser output.
             diagnostics.emit(error)
+            try finalizeDiagnostics()
             throw ExitCode.failure
+        } catch {
+            try finalizeDiagnostics()
+            throw error
         }
-        try finalizeDiagnostics()
     }
 }