* Fix implicit block syntax deprecation warnings in `user_spec.rb`
```
The implicit block expectation syntax is deprecated, you should pass
a block rather than an argument to `expect` to use the provided block
expectation matcher or the matcher must implement
`supports_value_expectations?`.
e.g `expect { value }.to change `User#local_avatar_attachment``
not `expect(value).to change `User#local_avatar_attachment``
```
```
The implicit block expectation syntax is deprecated, you should
pass a block rather than an argument to `expect` to use the provided
block expectation matcher or the matcher must implement
`supports_value_expectations?`.
e.g `expect { value }.to raise Exception`
not `expect(value).to raise Exception`
```
* Adjust context phrasing to adhere to Rubocop guidelines
"^when" instead of "^WHEN"
* Adjust `require` statement to use interpolation
Appeases Rubocop complaint for String concatenation being used instead
of String interpolation.
* Use `specify` instead of `it` for no implicit subject example
Ivan Kuchin