Include Benchmark Client version information in the result JSON

This part of the JSON schema isn't required yet. When missing, the version
is assumed to be -∞

benchmark/space/__init__.py

@@ -223,6 +223,16 @@ def modify_device_info(device_info):
     return device_info
 
 
+def benchmark_client_info() -> dict:
+    """Metadata about the Benchmark Client itself."""
+
+    from ..version import version
+
+    return {
+        'client_version': version,
+    }
+
+
 def benchmark_thread(ctx):
     with G.progress_lock:
         G.progress_status = "Collecting system information."
@@ -252,7 +262,8 @@ def benchmark_thread(ctx):
         "blender_version": system_info.getBlenderVersion(ctx),
         "system_info": modify_system_info(blender_system_info),
         "device_info": modify_device_info(blender_device_info),
-        "scenes": all_stats if all_stats else {}
+        "scenes": all_stats if all_stats else {},
+        "benchmark_client": benchmark_client_info(),
     })
 
     with G.progress_lock: