Remove Dockerfile

Hubble CLI binary already gets shipped as a part of the Cilium Agent
image, so let's not maintain yet another image.

- Remove Dockerfile and build-images-release.yaml.
- Put release.yml in the release GitHub environment.

Signed-off-by: Michi Mutsuzaki <[email protected]>

.github/ISSUE_TEMPLATE/release.md

@@ -78,7 +78,7 @@ title: 'vX.Y.Z release'
       git push origin "v$NEW_RELEASE"
 
 - [ ] Ping [`hubble-maintainers` team] on Slack to get an approval to run
-      [Image Release Build workflow].
+      [Release workflow].
 - [ ] Wait for the [`Create a release` workflow] to finish.
 - [ ] Find the release draft in the [Releases page]. Copy and paste release notes from
       CHANGELOG.md, and click on `Publish release` button.
@@ -95,7 +95,7 @@ title: 'vX.Y.Z release'
      and then open a pull request against the `main` branch, get it reviewed and merged.
 
 [Cilium release tool]: https://github.com/cilium/release
-[Image Release Build workflow]: https://github.com/cilium/hubble/actions/workflows/build-images-release.yaml
+[Release workflow]: https://github.com/cilium/hubble/actions/workflows/release.yml
 [`hubble-maintainers` team]: https://github.com/orgs/cilium/teams/hubble-maintainers
 [Releases page]: https://github.com/cilium/hubble/releases
 [Cilium Slack #general channel]: https://cilium.slack.com/archives/C1MATJ5U5

.github/renovate.json5

@@ -9,7 +9,6 @@
   "gitAuthor": "renovate[bot] <[email protected]>",
   "includePaths": [
     ".github/workflows/**",
-    "Dockerfile",
     "go.mod",
     "go.sum",
     "Makefile",

.github/workflows/release.yml

@@ -9,6 +9,7 @@ name: Create a release
 jobs:
   build:
     name: Create Release
+    environment: release
     if: github.repository == 'cilium/hubble'
     runs-on: ubuntu-24.04
     steps: