Spaces in Font's name are not escaped

Cloudinary supports all of Google's fonts https://support.cloudinary.com/hc/en-us/articles/203352832-What-is-the-list-of-supported-fonts-for-text-overlay-transformation- and some of them have spaces on them, for example, "Open Sans"

But unlike Text Transformation where spaces are escaped https://github.com/cloudinary/cloudinary_gem/blob/28a9ee65d24c6bac0654919a5a76de95cf356510/lib/cloudinary/utils.rb#L399 font family aren't https://github.com/cloudinary/cloudinary_gem/blob/28a9ee65d24c6bac0654919a5a76de95cf356510/lib/cloudinary/utils.rb#L452

resulting in an invalid URL

```ruby
[1] pry(main)> Cloudinary::VERSION
=> "1.20.0"
[2] pry(main)> url = Cloudinary::Utils.cloudinary_url("coffee_cup.jpg", transformation: [
{overlay: {font_family: "Open Sans", text: "Text with spaces", font_size: 10}}
])
=> "http://res.cloudinary.com/cookpad/image/upload/l_text:Open Sans_10:Text%20with%20spaces/coffee_cup.jpg"
[3] pry(main)> URI.parse url
URI::InvalidURIError: bad URI(is not URI?): "http://res.cloudinary.com/cookpad/image/upload/l_text:Open Sans_10:Text%20with%20spaces/coffee_cup.jpg"
```

Start in lib/cloudinary/utils.rb, comparing the text transformation escaping around line 399 with the font-family handling around line 452. Reproduce the Open Sans example from the issue and verify that the generated Cloudinary URL escapes spaces in the font name and can be parsed as a valid URI.

Vom Indexierungsmodell aus dem Issue-Text verfasst.