Logging at level: debug Configuration file: /github/workspace/./_config.yml GitHub Pages: github-pages v232 GitHub Pages: jekyll v3.10.0 Theme: jekyll-theme-primer Theme source: /usr/local/bundle/gems/jekyll-theme-primer-0.6.0 Requiring: jekyll-github-metadata Requiring: jekyll-seo-tag Requiring: jemoji Requiring: jekyll-coffeescript Requiring: jekyll-commonmark-ghpages Requiring: jekyll-gist Requiring: jekyll-github-metadata Requiring: jekyll-paginate Requiring: jekyll-relative-links Requiring: jekyll-optional-front-matter Requiring: jekyll-readme-index Requiring: jekyll-default-layout Requiring: jekyll-titles-from-headings GitHub Metadata: Initializing... Source: /github/workspace/. Destination: /github/workspace/./_site Incremental build: disabled. Enable with --incremental Generating... EntryFilter: excluded /README.md Reading: _posts/2015-09-25-how-to-undo-your-git-failure.md Reading: _posts/2016-02-09-what-is-version-control.md Reading: _posts/2016-04-17-do-not-go-gentle-into-that-good-night.md Reading: _posts/2016-07-23-a-better-hello-world.md Reading: _posts/2017-01-01-github-flow.md Reading: _posts/2018-05-09-four-lessons-after-eleven-years-in-silicon-valley.md Reading: _posts/2018-12-01-what-the-heck-is-a-callback.md Reading: _posts/2018-12-10-clean-coding.md Reading: _posts/2019-02-15-learn-react-js.md Reading: _posts/2019-02-20-digital-minimalism.md github-pages 232 | Error: (/github/workspace/_data/timeline.yml): mapping values are not allowed in this context at line 4 column 21