As per Gridsome documentation
Files in this directory will be copied directly to
distduring build
So in order for the _redirects file to get copied to dist for Netlify to process, you need to place it in the static directory in the project.
As per Gridsome documentation
Files in this directory will be copied directly to
distduring build
So in order for the _redirects file to get copied to dist for Netlify to process, you need to place it in the static directory in the project.