Blog post: Why GitLab is building Meltano, an open source platform for ELT pipelines

Closes #7725 (closed)

Checklist for writer

• Link to issue added, and set to close when this MR is merged
• Add disclaimer copy to the top of your blog post file: https://about.gitlab.com/handbook/marketing/blog/unfiltered/#link-to-disclaimer
• Blog post file formatted correctly, including any accompanying images
• unfiltered category entered in frontmatter
• Review app checked for any formatting issues
• Reviewed by fellow team member: Done by Emilie Schario at meltano/meltano!1628 (closed)
• Assign to someone on your team with maintainer access to merge (that's me!)

/label ~"unfiltered"