fix: replace deprecated ::set-output in release workflow

[rodet]

The release workflow uses the deprecated ::set-output syntax (removed in newer GitHub Actions runner versions) to read the Node.js version from .nvmrc.

File: .github/workflows/release.yml, line 32

Current:

run: echo ::set-output name=NODE_VERSION::$(cat .nvmrc)

Fix:

run: echo "NODE_VERSION=$(cat .nvmrc)" >> $GITHUB_OUTPUT

See GitHub docs.