Remove extra docker draft publish tags

Draft PRs should not publish with the base branch as a tag, and
the extra SHA tag without the build- prefix was redundant and we want
to encourage the use of the tags with build- prefix only.

Change-type: minor
Signed-off-by: Kyle Harding <[email protected]>

Author: klutchell

.github/workflows/flowzone.yml

@@ -462,8 +462,6 @@
         ${{ matrix.image }}
       labels: *dockerMetaLabels
       tags: |
-        type=raw,value=${{ github.base_ref || github.ref_name }}
-        type=raw,value=${{ github.event.pull_request.head.sha }}
         type=raw,value=build-${{ github.event.pull_request.head.sha }}
         type=raw,value=build-${{ github.event.pull_request.head.ref }}
       flavor: |