Add digest field to image block in values.yaml

[unitmatrix]

This pull request adds a digest field to the image block in the values.yaml file. The digest field allows specifying the exact image digest to pull, ensuring that the correct image version is used.

Changes include:

• Added digest field to the image block in values.yaml

This change does not introduce any breaking changes and is backward compatible. The digest field is already utilized in the _helpers.tpl file, ensuring that the specified digest is used when constructing the image name.

[undera]

What happens if digest is not specified? Will it work as before?

[unitmatrix]

If the digest field is not specified, the behavior will remain the same as before. The image will be pulled based on the tag field or the default chart appVersion if the tag is not specified. The digest field is optional and only used when explicitly provided, ensuring backward compatibility and no changes to the existing functionality.

[undera]

Thank you for explaining