fix: change Kong Gateway Enterprise default image to Ubuntu

[programmer04]

PR #867 bumped image from 3.3.-alpine to 3.4-alpine despite failures in tests (this and that) it was successfully merged. A fix for this to not allow merging is presented in

• fix(ci): fail integration-tests-passed when tests don't pass #869

Since 3.4 the Alpine image is no longer built, the recommended one is Ubuntu so this PR is setting it.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (f5395af) 56.85% compared to head (46b0be9) 60.31%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #868      +/-   ##
==========================================
+ Coverage   56.85%   60.31%   +3.45%     
==========================================
  Files          49       49              
  Lines        4024     4024              
==========================================
+ Hits         2288     2427     +139     
+ Misses       1452     1293     -159     
- Partials      284      304      +20     

Flag	Coverage Δ
integration-test	60.31% <ø> (+3.45%)	⬆️

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Files	Coverage Δ
pkg/clusters/addons/kong/addon.go	63.81% <ø> (+15.57%)	⬆️

... and 6 files with indirect coverage changes

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[pmalek]

Given that integration-tests-passed check if required how did we end up merging #867 🤔 ? Wasn't that the case at the time it was merged? Did the required checks changed since then?

[pmalek]

Given that integration-tests-passed check if required how did we end up merging #867 🤔 ? Wasn't that the case at the time it was merged? Did the required checks changed since then?

I see https://github.com/Kong/kubernetes-testing-framework/pull/869/files