Fix dockerfile target result in case of success

[olblak]

While doing some test with the dockerfile autodiscovery, I noticed a regression in the dockerfile plugin resource.
Where the result is not set if nothing change

TARGETS
========

registry.access.redhat.com/ubi9/ubi
-----------------------------------

**Dry Run enabled**

✔ The line #12, matched by the keyword "FROM" and the matcher "registry.access.redhat.com/ubi9/ubi", is correctly set to "FROM registry.access.redhat.com/ubi9/ubi:9.2-489".
- - 

Test

To test this pull request, you can run the following commands:

cp <to_package_directory>
go test

Additional Information

Tradeoff

Potential improvement

[dduportal]

Confirmed that this PR fixes the error: we have the error with https://github.com/jenkinsci/docker-ssh-agent/blob/master/updatecli/updatecli.d/git-windows.yml (the GHA checks are red for now, using latest updatecli).

Tried locally, comparing latest updatecli and a build of the upcoming 0.53.0: the problem is gone with 0.53.0.
Thanks!