fix: skip the release job when there's nothing to publish

[zanlucathiago]

What's wrong

The Release workflow runs on every push to main. When a commit has no pending changeset — a Dependabot bump, a docs change, any routine merge — changesets/action still runs the publish script, which tries to re-publish the current version. That version is already on npm, so it should no-op, but changesets 2.31.0 crashes parsing npm's "already published" response:

error TypeError: Cannot read properties of undefined (reading 'includes')
    at isAlreadyPublishedError (@changesets/cli/.../changesets-cli.cjs.js:873:17)

The result is a red X on every routine merge — see run #27, triggered by merging the Dependabot PR #39. The next merge (e.g. #40) would fail the same way. The published package itself is fine; 0.4.0 shipped correctly from the #38 release.

The fix

A guard step runs changesets/action only when there's actually something to do — a changeset is pending, or the local package.json version isn't the one published on npm:

- name: Anything to release?
  id: release_needed
  run: |
    pending=$(find .changeset -maxdepth 1 -name '*.md' ! -name 'README.md' | wc -l | tr -d ' ')
    local_version=$(node -p "require('./package.json').version")
    published_version=$(npm view xls-reader version 2>/dev/null || echo none)
    ...

Behavior across the three cases:

Merge	Pending changeset?	local vs npm	Result
Feature PR (has changeset)	yes	—	runs → opens/updates the version PR
"Version Packages" PR	no	differ	runs → publishes the bumped version
Dependabot / docs / chore	no	equal	skips (was crashing)

Notes

• Can't fully exercise a release workflow locally; I validated the YAML parses and dry-ran the guard logic against the current repo state (pending=0, 0.4.0 == 0.4.0 → skip). The real paths only run on merge to main.
• Infra-only change, no changeset (a workflow tweak shouldn't version the package).
• The eventual "proper" fix is upgrading @changesets/cli once 3.0.0 is stable and past the cooldown; today only 3.0.0-next.* prereleases carry the fix, so this guard sidesteps the bug in the meantime.