fix(gatsby-theme-docz): removed unused gatsby-plugin-manifest

[alchi126]

Description

gatsby-theme-docz has a dependency on gatsby-plugin-manifest, which in turn relies on a package called sharp that's causes install issues on Windows x64 machines.

As gatsby-plugin-manifest serves a specific use case (see specs here) and is actually never used in gatsby-theme-docz, it'd be a great help to remove it from the theme all together.

[rakannimer]

Good catch ! Thanks 👍

[alchi126]

Thanks for the merge, and all the great work you've been doing with docz!

[alchi126]

When is the next release expected to be? Due to external download restrictions on my work machine I could only get the package via npm.

On a related note: docz also has an unused dependency on gatsby-theme-docz. I don't think it'd cause any issues, providing the version gets bumped after the next release of gatsby-theme-docz, but I'll gladly submit a PR to remove if it helps.

[wj2061]

I can't use docz@2.2.0 for the same reason , now I have to use docz@2.3.0-alpha.13 instead.