Update README.md

Author: lzl199704

README.md

@@ -12,7 +12,7 @@ The RadImageNet database includes 1.35 million annotated CT, MRI, and ultrasound
 
 ## Top1 and Top5 Accuracy
 | Model Name        | Top1 Accuracy    | Top5 Accuracy  |
-| ------------- |:-------------:| -----:|
+| ------------- |:---------:| -----:|
 | InceptionResNetV2      | 74.0% | 94.3% |
 | ResNet50      | 72.3%  | 94.1% |
 | DenseNet121 | 73.1%   | 96.1% |