Py-swagger-ui

**Interface changes**: none.

- Improvement (a11y): add titles and ARIA labels to elements (via 4130, 4127)
- Bugfix (rendering): improve spacing and punctuation in parameter enum display (via 4144)
- Bugfix (rendering): right-align tag expand/collapse button, even when the tag has no description (via 4129)
- Bugfix (try-it-out): surface parameter validation error messages to OAS3 users (via 4162)

**Interface changes**: none.

- Improvement: allow `urls` option to be specified in Docker (via 4044)
- Improvement: give `Content-Disposition: attachment` priority over `Content-Type` when choosing to display or offer download of a response (via 4140)
- Performance: remove produces/consumes default setters from `OperationContainer` (via 4137)
- Bugfix: support cross-frame object reference quirk in IE11 (4128)
- Bugfix: force `border-box` box styling in main stylesheet (via 4121)
- Bugfix: bail out Servers selection component to the first server if the currently selected server URL becomes invalid (via 4139)

**Interface changes**: none.

- Enhancement (docker): added a symlink to the nginx directry so `swagger.json` can be modified within the container (via 4024)
- Enhancement (packaging): `swagger-ui` npm module now includes Standalone Preset (via 4101)
- Enhancement (try-it-out): added extraction of quoted file name from Content-Disposition header (via 4035)
- Enhancement (docker): added option to serve Swagger-UI on a custom port within the container (via 4086)
- Bugfix: removed extraneous required prop in ModelCollapse that was causing Proptypes errors in users' React projects (via 4100)
- Bugfix: `format: uuid` is no longer case-sensitive (via 4102)

**Interface changes**: one core plugin API change, no public API changes.

Introduced a breaking function signature change to `errActions.newThrownErr` action creator (from `(err, action)` to `(err)`) and `err_new_thrown_err` action payload (stopped nesting error content under `error` key in payload, now the error _is_ the payload).

- Feature: added error catcher for statePlugin interfaces; prevents errors in plugin code from crashing entire application instance (via 4067)
- The only downside to this is that some errors are now a bit harder to trace! Set a breakpoint at `console.error` and walk down the stack to see what's going wrong.
- Feature: display error content when definition/config load fails (via 4069)
- Feature: display parameter enums, defaults, and examples when not in Try-It-Out mode (via 3977)
- Improvement: added `hasOwnProperty` checks to a handful of `for...in` loops (via 4043)
- Improvement: now using nginx `location` to set Docker base url instead of moving things around the filesystem (via 4073)
- Improvement: brought parameter model property description styling in line with styling for.... everything else (via 4075)
- Bugfix: check for `Promise` on global/window object, which makes IE11 a very happy browser (via 4077)
- Housekeeping: used `zopflipng` to compress PNG assets in repo (via 4037)
- Housekeeping: added maintainer documentation for PR merging workflow (via 4076)

- Bugfix: added `this` binding to `afterLoad` plugin interface to expose raw plugin context (via 4059)
- Performance regression fix: Models section no longer makes wasteful renders due to `specPath` inequality (via 4060)

**Interface changes**:
- plugins may now expose an `afterLoad` method in order to make changes to the top-level system after the plugin is merged into the system.
- the undocumented `initialState` parameter now allows removal of default keys by setting its value to `undefined` in the parameter.

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- Feature: `afterLoad` plugin interface is now available (via 4049)
- Bugfix: non-object values are no longer sent to `updateJsonSpec` from `parseToJson` (via 1596)
- Bugfix: path-level parameters no longer create empty `default` tag groups (via 4051)