Add ca-certificates to debian-base

[hakman]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Using this image as base for other projects sometimes requires CA certificates for access to cloud APIs.
Adding CA certificates to the base image makes it easy to use ko as the build tool.

xRef:
https://github.com/golang/go/blob/go1.24.4/src/crypto/x509/root_linux.go#L9-L11

// Possible certificate files; stop after finding one.
var certFiles = []string{
	"/etc/ssl/certs/ca-certificates.crt",                // Debian/Ubuntu/Gentoo etc.

Which issue(s) this PR fixes:

None

Special notes for your reviewer:

The change is the compressed image size is very small, about 120KB (41,7MB -> 41.82MB).

Does this PR introduce a user-facing change?

Adds ca-certificates to debian-base image

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: hakman / name: Ciprian Hacman (ead3ad8)

[hakman]

/cc @cpanato

[cpanato]

lgtm in general

/assign @saschagrunert for another set of eyes

/approve
/hold

[k8s-ci-robot]

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In response to this:

lgtm in general

/assign @saschagrunert for another set of eyes

/approve
/hold

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cpanato, hakman, saschagrunert

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Needs approval from an approver in each of these files:

• images/build/debian-base/OWNERS [cpanato,saschagrunert]

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[saschagrunert]

Thanks!

/unhold