Metamask OpenRPC Docusaurus Plugin - Deprecated

## 📝 Summary
The `metamask/docusaurus` plugin is deprecated from the perspective of the OpenRPC team. Our new OpenRPC ecosystem has received major version updates across all tools. In particular, the generator now uses the latest Gatsby, Material-UI, and React ecosystem. The old Docusaurus plugin cannot be maintained or updated, and the future of OpenRPC relies on features present in these major versions.

## 🔍 Background
- **Deprecated**: `metamask/docusaurus` plugin
- **Maintained**: New OpenRPC ecosystem with major version bumps
- **Relevant Tool**: `open-rpc/generator` now at `2.x.x`, built on Gatsby, Material-UI, React

## 📚 Links
| Resource | URL |
| ----------------------------- | --------------------------------------------------------- |
| OpenRPC mono-repo | https://github.com/open-rpc/tools |
| OpenRPC generator (`2.x.x`) | https://github.com/open-rpc/generator |

## 🤔 Proposal
1. **Version bump** the generator to `2.x.x`.
2. **Increase** CI Node version to `>= v20.x.x`.
3. **Rollback** the previous Docusaurus change (if already merged).

Alternative Proposal
1. **Version bump** the generator to `2.x.x`.
2. **(Optional)** Increase CI Node version to `>= v20.x.x`.
3. ** Fork** and update the docusaurus plugin to support the major version updates.
@shanejonas for suggestions on what you might add or fix

These steps ensure we’re using the latest ecosystem, unlock new features, and reduce maintenance burden.

## 🚀 Suggested Resolution
- Revert the Docusaurus-related commit (if applied).
- Update `package.json` (or the CI config) to use:
- `@open-rpc/generator@^2.x.x`
- `node >= 20.x.x` (optional)

## 💻 Environment
| Key | Value |
| ------------ | --------------------------- |
| Generator | `@open-rpc/generator@2.x.x` |
| Node | `>= 14.x.x` (current) |
| Proposed | `>= 20.x.x` |

## 📄 Additional Context
Any local-docs concerns have been addressed in the `2.x.x` release of the generator. If there are further questions or edge cases, please comment below!