Update ubuntu Docker tag to v26

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
ubuntu	final	major	22.04 → 26.04
ubuntu	final	major	20.04 → 26.04

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Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about these updates again.

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• If you want to rebase/retry this PR, check this box

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[renovate]

⚠️ Artifact update problem

Renovate failed to update artifacts related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: dockers/verifydeb/Dockerfile

Post-upgrade command './gradlew --write-verification-metadata pgp,sha256 --export-keys help' has not been added to the allowed list in allowedCommands

File name: dockers/signing/Dockerfile

Post-upgrade command './gradlew --write-verification-metadata pgp,sha256 --export-keys help' has not been added to the allowed list in allowedCommands

File name: dockers/install/debian/Dockerfile

Post-upgrade command './gradlew --write-verification-metadata pgp,sha256 --export-keys help' has not been added to the allowed list in allowedCommands

File name: dockers/install/apt/Dockerfile

Post-upgrade command './gradlew --write-verification-metadata pgp,sha256 --export-keys help' has not been added to the allowed list in allowedCommands

[renovate]

Renovate Ignore Notification

Because you closed this PR without merging, Renovate will ignore this update. You will not get PRs for any future 26.x releases. But if you manually upgrade to 26.x then Renovate will re-enable minor and patch updates automatically.

If you accidentally closed this PR, or if you changed your mind: rename this PR to get a fresh replacement PR.