Fetch JSON spec from Artifacts Snapshot API

[pquentin]

We were still using the Artifacts API, which has no notion of "8.x", which is why builds were still failing: https://github.com/elastic/elasticsearch-specification/actions/runs/11064313424/job/30741882039.

This can be tested with:

make setup
npm install .github/download-artifacts
node .github/download-artifacts/index.js --branch 8.x
git status   # notice that we did change specification/_json_spec, it's just not formatted yet
make contrib
git status   # after formatting, there's no change left

[pquentin]

This had no effect for some time now.

[pquentin]

We only use --branch now.

[pquentin]

This is largely copied over from clients-flight-recorder.

[github-actions]

The backport to 7.17 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-7.17 7.17
# Navigate to the new working tree
cd .worktrees/backport-7.17
# Create a new branch
git switch --create backport-2949-to-7.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 0464df58867761123eec71e31bde5575189fceb3
# Push it to GitHub
git push --set-upstream origin backport-2949-to-7.17
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-7.17

Then, create a pull request where the base branch is 7.17 and the compare/head branch is backport-2949-to-7.17.

[github-actions]

The backport to 8.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-8.x 8.x
# Navigate to the new working tree
cd .worktrees/backport-8.x
# Create a new branch
git switch --create backport-2949-to-8.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 0464df58867761123eec71e31bde5575189fceb3
# Push it to GitHub
git push --set-upstream origin backport-2949-to-8.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-8.x

Then, create a pull request where the base branch is 8.x and the compare/head branch is backport-2949-to-8.x.

[github-actions]

The backport to 8.15 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-8.15 8.15
# Navigate to the new working tree
cd .worktrees/backport-8.15
# Create a new branch
git switch --create backport-2949-to-8.15
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 0464df58867761123eec71e31bde5575189fceb3
# Push it to GitHub
git push --set-upstream origin backport-2949-to-8.15
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-8.15

Then, create a pull request where the base branch is 8.15 and the compare/head branch is backport-2949-to-8.15.