Choosing Docker runtime via inserting build command in Buildspec

[dave-007]

During this step in lab:

Add the Build stage:
...
    Select runtime as Docker

I don't have an option for Docker, so build fails. To get this working, From AWS console I needed to:
In CodeBuild edit the eks-build-project, and choose Edit Buildspec, and chose insert build commands
I changed lines 12-17 to:

phases:
  install:
    runtime-versions:
      docker: 18