While alphabetical ordering works great with image tags that contain a RFC3339 timestamp, it's not suitable for CI build IDs, as these are numbers with no padding.

I propose we introduce a new ordering option called numerical to be able to correct detect the latest build for tags in the format <PREFIX>-<BUILD_ID>.

Example:

kind: ImagePolicy
spec:
  filterTags:
    pattern: '^main-[a-fA-F0-9]+-(?P<id>.*)'
    extract: '$id'
  policy:
    numerical:
      order: asc

Given the tags main-845d3a80-100 and main-3e32dc8a-2 the numerical policy, unlike alphabetical, will chose main-3e32dc8a-100 as the latest build.