Getting "No info found in package.json for @angular/cli" on "ng add @nebular/theme"

### Issue type

**I'm submitting a ...** (check one with "x")

* [x] bug report
* [ ] feature request

### Issue description

**Current behavior:**

When I run "ng add @nebular/theme" by following the guide at (https://akveo.github.io/nebular/docs/guides/install-nebular#using-angular-cli) it gives me the following error:
`No info found in package.json for @angular/cli`

**Expected behavior:**

Nebular added successfully

**Steps to reproduce:**

Type `ng add @nebular/theme` on console

### Other information:

**npm, node, OS, Browser**
```
Node: v12.16.1
npm: 6.13.4
OS: Windows 10
Browser: Firefox
```

**Angular, Nebular**
`package.json` after running `ng add @nebular/theme`
```
{
"name": "client",
"version": "0.0.0",
"scripts": {
"ng": "ng",
"start": "node server.js",
"build": "ng build",
"build:prod": "ng build --prod --output-path dist",
"test": "ng test",
"lint": "ng lint",
"e2e": "ng e2e",
"postinstall": "ng build --prod --output-path dist"
},
"private": true,
"dependencies": {
"@angular/animations": "^9.1.1",
"@angular/cli": "^9.1.1",
"@angular/common": "^9.1.1",
"@angular/compiler": "^9.1.1",
"@angular/compiler-cli": "^9.1.1",
"@angular/core": "^9.1.1",
"@angular/elements": "^9.1.1",
"@angular/forms": "^9.1.1",
"@angular/platform-browser": "^9.1.1",
"@angular/platform-browser-dynamic": "^9.1.1",
"@angular/router": "^9.1.1",
"@nebular/theme": "^5.0.0",
"ag-grid-angular": "^23.0.3",
"ag-grid-community": "^23.0.0",
"alertifyjs": "^1.13.1",
"document-register-element": "^1.7.2",
"express": "^4.17.1",
"lodash.merge": "^4.6.2",
"papaparse": "^5.2.0",
"rxjs": "^6.5.5",
"tslib": "^1.10.0",
"zone.js": "^0.10.3"
},
"devDependencies": {
"@angular-devkit/build-angular": "^0.901.1",
"@angular/language-service": "^9.1.1",
"@schematics/angular": "^9.1.1",
"@types/jasmine": "^3.5.10",
"@types/jasminewd2": "~2.0.3",
"@types/node": "^12.12.35",
"codelyzer": "^5.2.2",
"jasmine-core": "~3.5.0",
"jasmine-spec-reporter": "~4.2.1",
"karma": "~4.3.0",
"karma-chrome-launcher": "~3.1.0",
"karma-coverage-istanbul-reporter": "~2.1.0",
"karma-jasmine": "~2.0.1",
"karma-jasmine-html-reporter": "^1.5.3",
"protractor": "~5.4.3",
"ts-node": "~8.3.0",
"tslint": "~5.18.0",
"typescript": "~3.7.5"
}
}

```