Replacing invalid schema markup with json-ld syntax
Replacing invalid schema markup with json-ld syntax

Previous markup missing both `itemscope` and `itemtype` and [isn't valid](https://search.google.com/structured-data/testing-tool/u/0/#url=https%3A%2F%2Fprogressivetooling.com%2F). Since not marked-up in body and in keeping this in the `<head>`, introducing JSON-LD instead, declaring type, etc.
GoogleChromeLabs/progressive-tooling,GoogleChromeLabs/progressive-tooling