Replace scripts/get_data.py to get_data.py. (#775)

For the consitency in this page, replace scripts/get_data.py to get_data.py.

Author: ChiahungTai

scripts/README.md

@@ -19,7 +19,7 @@
 python get_data.py qlib_data --target_dir ~/.qlib/qlib_data/cn_data --region cn
 
 # 1min  data (Optional for running non-high-frequency strategies)
-python scripts/get_data.py qlib_data --target_dir ~/.qlib/qlib_data/qlib_cn_1min --region cn --interval 1min
+python get_data.py qlib_data --target_dir ~/.qlib/qlib_data/qlib_cn_1min --region cn --interval 1min
 ```
 
 ### Download US Data