#### Describe the bug
For some REST API endpoints we use [Google Cloud API Custom Methods](https://cloud.google.com/apis/design/custom_methods) URL design like `/api/resource:customVerb`.

These worked with `axios` prior to **0.27.1** but now they result in an error like:

`AxiosError { message: "Unsupported protocol /api/resource:', code: "ERR_BAD_REQUEST", ... }`

#### To Reproduce
Try to have `axios` get a relative URL with a colon in it, e.g.
```js
axios.get("/api/resource:customVerb");
```

#### Expected behavior
Should continue working as it did before version **0.27.1**.

#### Environment
 - Axios Version: 0.27.1
 - Browser: Microsoft Edge 100.0.1185.50
 - Node.js Version: 16.14.2
 - OS: Windows 10 Pro

#### Additional context/Screenshots
n/a

lib/adapters/xhr.js
}
    }
    
    if ('setRequestHeader' in request) {
      utils.forEach(requestHeaders, function setRequestHeader(val, key) {
        if (typeof requestData === 'undefined' && key.toLowerCase() === 'content-type') {
          
          delete requestHeaders[key];
        } else {
          
          request.setRequestHeader(key, val);
        }
      });
    }
    
    if (!utils.isUndefined(config.withCredentials)) {
      request.withCredentials = !!config.withCredentials;
    }
    
    if (responseType && responseType !== 'json') {
      request.responseType = config.responseType;
    }
    
    if (typeof config.onDownloadProgress === 'function') {
      request.addEventListener('progress', config.onDownloadProgress);
    }
    
    if (typeof config.onUploadProgress === 'function' && request.upload) {
      request.upload.addEventListener('progress', config.onUploadProgress);
    }