Use precise commit ranges for git-cliff changelog generation

[Copilot]

The changelog generation was using --latest flag, which doesn't provide control over commit ranges. This changes it to calculate precise ranges based on event type.

Changes

• Added commit range detection step that determines the appropriate range:

  • Release (v* tag): previous_v_tag..current_v_tag
  • Prerelease (push to main): latest_v_tag..HEAD
  • First release: current_tag or HEAD if no tags exist

• Modified git-cliff invocation to consume the calculated range instead of --latest

Implementation

- name: Determine commit range for changelog
  run: |
    if [[ $GITHUB_REF == refs/tags/v* ]]; then
      CURRENT_TAG="${GITHUB_REF#refs/tags/}"
      PREVIOUS_TAG=$(git tag -l "v*" --sort=-version:refname | grep -F -x -v "${CURRENT_TAG}" | head -n 1)
      echo "args=${PREVIOUS_TAG:+$PREVIOUS_TAG..}${CURRENT_TAG}" >> $GITHUB_OUTPUT
    else
      LATEST_TAG=$(git tag -l "v*" --sort=-version:refname | head -n 1)
      echo "args=${LATEST_TAG:+$LATEST_TAG..}HEAD" >> $GITHUB_OUTPUT
    fi

- name: Generate a changelog
  with:
    args: ${{ steps.commit-range.outputs.args }} --strip header

Uses grep -F -x -v for exact string matching to handle version tags with special characters (e.g., dots in v1.0.1).

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