Improperly defined peer dependencies

[Muthaias]

Description

The following peer dependencies can't be met:

npm ERR! peer dep missing: prop-types@>15, required by @tinacms/form-builder@0.3.2
npm ERR! peer dep missing: prop-types@>15, required by @tinacms/react-sidebar@0.1.2
npm ERR! peer dep missing: prop-types@>15, required by @tinacms/react-toolbar@0.1.0
npm ERR! peer dep missing: prop-types@>15, required by @tinacms/form-builder@0.3.2

Steps to reproduce

yarn add "tinacms@0.19.0"
yarn add "prop-types@>15"
Note that prop-types currently only goes to version 15.x which is not covered by this. I would expect @>=15 here instead.

Expected result

Being able to install the required peer dependencies

Actual result

No available peer dependencies that meets requirements.

Environment

node: v10.16.0
npm: 6.9.0

Tinacms Package Versions

├─┬ tinacms@0.19.0
│ ├── @tinacms/alerts@0.1.2
│ ├── @tinacms/core@0.7.4
│ ├─┬ @tinacms/fields@0.10.0
│ ├─┬ @tinacms/form-builder@0.3.2
│ ├─┬ @tinacms/forms@0.4.1
│ ├── @tinacms/icons@0.9.0
│ ├── @tinacms/media@0.1.0
│ ├── @tinacms/react-alerts@0.1.2
│ ├─┬ @tinacms/react-core@0.2.11
│ ├─┬ @tinacms/react-forms@0.1.2
│ ├── @tinacms/react-modals@0.1.2
│ ├── @tinacms/react-screens@0.1.1
│ ├─┬ @tinacms/react-sidebar@0.1.2
│ ├─┬ @tinacms/react-toolbar@0.1.0
│ ├── @tinacms/styles@0.4.2
│ └─┬ react-tinacms-editor@0.5.0
│   ├─┬ @tinacms/react-forms@0.1.2-alpha.0

[kendallstrautman]

Improved via #1129?