[BUG] wrktool in Circuit Breaker doesn't work successfully

[tomoyk]

Describe the bug
A clear and concise description of what the bug is.

Platform
ECS

To Reproduce
Steps to reproduce the behavior:

1. move to aws-app-mesh-examples/walkthroughs/howto-circuit-breakers
2. read README and run commands
3. the command ./infrastructure/ecs-service is failed
4. check the service's log on ECS

ECS task's error log:

OCI runtime create failed: runc create failed: unable to start container process: exec: "python3": stat python3: no such file or directory

Expected behavior
A container runs successfully from wrktool container image.

Config files, and API responses
This dockerfile is used for building wrktool container image.

https://github.com/aws/aws-app-mesh-examples/blob/5d9a248129e7da3b9cd37e868e491c134df87d20/walkthroughs/howto-circuit-breakers/src/wrktool/Dockerfile

Additional context
The line as below might be root cause of this error. Python3 has dependency for Python3 pip, so that Python3 package is uninstalled by this command.

yum -y remove python3-pip git-core && \

When I commented out this code, the error doesn't occur.