[K8s] Latest Docker Image not being pulled if older image exists locally

[aswanthkrishna]

When launching a SkyPilot task with a Docker image on local Kubernetes, the system does not pull the latest version of the image if an older version is already present locally.

This behavior appears to be due to the imagePullPolicy being set to IfNotPresent. based on discussion with @romilbhardwaj on slack, it might be useful to change to imagePullPolicy: Always

Version & Commit info:

• sky -v: 1.0.0-dev0
• sky -c: a726c7885184d4ab0791c65c08ee487aca311be9-dirty