Add proper support for working-directory & fix command builder (#772)

* fix: align other Docker executors to print action

* fix: formatting

* fix: add proper workdir support

* fix: replace script filepath after slice creation

* fix: match substring so it works for pwsh

+ rename containerPath to scriptPath to reflect what value it contains

pkg/runner/testdata/basic/push.yml

@@ -8,6 +8,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
+      - run: '[[ "$(pwd)" == "${GITHUB_WORKSPACE}" ]]'
       - run: echo ${{ env.TEST }} | grep value
       - run: env
       - uses: docker://node:12-buster-slim