fix: [CVE-2020-7753] Update remark to 13.0.0 (styleguidist#1710)

test: Fix tests — no idea what happened here 🍄

feat: Add `expand` option for sections and allow custom root section …

…options (styleguidist#1689)

fix: Fix broken assetsDir due to updated copy-webpack-plugin (stylegu…

…idist#1690)

Because copy-webpack-pluign was updated, the assetsDir was broken.
We need to update the config being passed to the plugin to make it
work again. Update the plugin to latest version 6.1.0 and update
the config and tests to make it work.

Fixes styleguidist#1676

fix: Handle visibleName with non-alphanumeric characters (styleguidis…

…t#1675)

Refs styleguidist/react-docgen-typescript#292

chore: Switch to Angular commit convention 🦆

Fixes styleguidist#1673

Fix: Update markdown-to-jsx (styleguidist#1599)

This updates the markdown-to-jsx package to v6.11.4 in order to patch a security vulnerability as reported at styleguidist#1596 and addressed here at quantizor/markdown-to-jsx#306

Fix: Fix navigation to sections with numbers in the name (styleguidis…

…t#1595)

Fixes styleguidist#1594

Fix: Show examples with targetIndex = 0 (styleguidist#1573)

Co-authored-by: Vladimir Akimov <[email protected]>

Fix: Fix missing FlowType enum values in prop description (styleguidi…

…st#1571)

In `ef4c109b`, the file `PropsRenderer.js` (located at
`src/client/rsg-components/Props/PropsRenderer.js`) was removed. In
`PropsRenderer.js`, the `renderExtra` method checked whether `getType`
for the argument to `renderExtra` was present:

```es6
function renderExtra(prop) {
  const type = getType(prop);
  if (!type) {
    return null;
  }
  ...
}
```

However, in `ef4c109b`, this method was replaced with `renderExtra.tsx`
and the condition was changed to:

```typescript
export default function renderExtra(prop: PropDescriptorWithFlow): React.ReactNode {
  const type = getType(prop);
  if (!prop.type || !type) {
    return null;
  }
```

Unfortunately, this extra condition has resulted in this method always
returning `null` for a Flow typed prop as `prop.type` is always `null`
as `prop.type` is never set.

This commit reverts the condition to what it was before the migration to
TypeScript.