fix_decord_sys_platform (#3682)

Author: zhangyubo0722

requirements.txt

@@ -42,7 +42,7 @@ unstructured
 networkx
 faiss-cpu
 ######## For Video #######
-decord==0.6.0; platform_machine=='x86_64' or platform_machine=='AMD64'
+decord==0.6.0; (platform_machine == 'x86_64' or platform_machine == 'AMD64') and sys_platform != 'darwin'
 ######## For NLP Tokenizer #######
 jieba
 sentencepiece