Failed to activate the atom-medium package

[Enter steps to reproduce:]

1. ...
2. ...

**Atom**: 1.41.0 x64
**Electron**: 4.2.7
**OS**: Mac OS X 10.15.1
**Thrown From**: [atom-medium](https://github.com/ericadamski/atom-medium-upload) package 2.0.1

### Stack Trace

Failed to activate the atom-medium package

```
At this._acquireAccessToken is not a function

TypeError: this._acquireAccessToken is not a function
at MediumClient.exchangeRefreshToken (/packages/atom-medium/node_modules/medium-sdk/lib/mediumClient.js:154:8)
at tryCatcher (/packages/atom-medium/node_modules/rxjs/util/tryCatch.js:6:31)
at BoundCallbackObservable._subscribe (/packages/atom-medium/node_modules/rxjs/observable/BoundCallbackObservable.js:204:64)
at BoundCallbackObservable.Observable._trySubscribe (/packages/atom-medium/node_modules/rxjs/Observable.js:172:25)
at BoundCallbackObservable.Observable.subscribe (/packages/atom-medium/node_modules/rxjs/Observable.js:160:93)
at storeToken (/packages/atom-medium/lib/authenticate.js:107:12)
at hasToken (/packages/atom-medium/lib/authenticate.js:63:9)
at authenticate (/packages/atom-medium/lib/authenticate.js:116:12)
at user (/packages/atom-medium/lib/client.js:15:12)
at User.componentDidMount (/packages/atom-medium/lib/components/user.jsx:57:9)
at ik (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:251:360)
at exports.unstable_runWithPriority (/packages/atom-medium/node_modules/scheduler/cjs/scheduler.production.min.js:18:437)
at fg (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:120:325)
at Yj (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:244:437)
at Lj (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:223:420)
at Rg (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:214:137)
at rk (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:279:43)
at /packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:282:301
at ck (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:224:210)
at zk (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:282:287)
at render (/packages/atom-medium/node_modules/react-dom/cjs/react-dom.production.min.js:286:416)
at /packages/atom-medium/lib/medium-upload-view.js:15:9)
at Object.activate (/packages/atom-medium/lib/medium-upload.js:18:33)
at Package.activateNow (/Applications/Atom.app/Contents/Resources/app/static/:11:3208914)
at activationCommandSubscriptions.add.commandRegistry.onWillDispatch.o (/Applications/Atom.app/Contents/Resources/app/static/:14:1879)
at Function.simpleDispatch (/Applications/Atom.app/Contents/Resources/app/static/:11:1211909)
at Emitter.emit (/Applications/Atom.app/Contents/Resources/app/static/:11:1213350)
at CommandRegistry.handleCommandEvent (/Applications/Atom.app/Contents/Resources/app/static/:11:349024)
at CommandRegistry.dispatch (/Applications/Atom.app/Contents/Resources/app/static/:11:347867)
at AtomEnvironment.dispatchApplicationMenuCommand (/Applications/Atom.app/Contents/Resources/app/static/:1:718772)
```

### Commands

```
-0:13.2.0 medium-upload:toggle (input.hidden-input)
```

### Non-Core Packages

```
atom-clock 0.1.17
atom-material-ui 2.1.3
atom-medium 2.0.1
export-html 3.1.0
gruvbox-plus-syntax 1.3.1
Hydrogen 2.13.1
hydrogen-python 0.0.8
jekyll 2.1.0
language-latex 1.2.0
latex 0.50.2
markdown-themeable-pdf 1.2.1
markdown-writer 2.11.9
platformio-ide-terminal 2.10.0
python-autopep8 0.1.3
python-indent 1.2.5
wordcount 3.1.0
```