add rtmpose coreml support (#1902)

Author: FishBigOcean

configs/mmpose/pose-detection_simcc_coreml_static-256x192.py

@@ -0,0 +1,14 @@
+_base_ = ['../_base_/torchscript_config.py', '../_base_/backends/coreml.py']
+
+ir_config = dict(input_shape=[192, 256], output_names=['simcc_x', 'simcc_y'])
+
+codebase_config = dict(type='mmpose', task='PoseDetection')
+
+backend_config = dict(model_inputs=[
+    dict(
+        input_shapes=dict(
+            input=dict(
+                min_shape=[1, 3, 256, 192],
+                max_shape=[1, 3, 256, 192],
+                default_shape=[1, 3, 256, 192])))
+])