feat: check if required binaries are present (#272)

* feat: check if required binaries are present

Previously the necessary binaries were copied over using the runner
container. This lead to issues in case your main container was using the
musl libc implementation.

Instead of copying over any binaries, the initContainer now checks if
the required binaries are present in the main container.

* feat: get rid of the init container

* fix: add _runner_file_commands

* fix: do not fail if _runner_file_commands does not exist

It seems that for container actions this directory does not exist.

packages/k8s/src/hooks/run-container-step.ts

@@ -104,7 +104,7 @@ export async function runContainerStep(
     try {
       core.debug(`Executing container step script in pod ${podName}`)
       return await execPodStep(
-        ['/__e/sh', '-e', containerPath],
+        ['sh', '-e', containerPath],
         pod.metadata.name,
         JOB_CONTAINER_NAME
       )
@@ -133,7 +133,7 @@ function createContainerSpec(
   podContainer.name = JOB_CONTAINER_NAME
   podContainer.image = container.image
   podContainer.workingDir = '/__w'
-  podContainer.command = ['/__e/tail']
+  podContainer.command = ['tail']
   podContainer.args = DEFAULT_CONTAINER_ENTRY_POINT_ARGS
 
   podContainer.volumeMounts = CONTAINER_VOLUMES