README.md in ddtrace-0.48.0

- old
+ new

@@ -4,11 +4,10 @@
 
 ## Quickstart
 
 1. Build Docker base images:
 
-    ```sh
-    #!/bin/bash
+    ```bash
     ./script/build-images
     ```
 
 2. Choose an application and follow instructions (in corresponding `README.md`.)
 