Case-insensitive search with JMESPath

Simple question: How to do a case-insensitive searching with JMESPath?

Let's say to search for `foo` in this JSON:

```
[
  "foo",
  "foobar",
  "barfoo",
  "bar",
  "baz",
  "barbaz",
  "FOO"
]
```

Here is the case-sensitive search query:

```
[?contains(@, 'foo')]
```

It will returns `["foo", "foobar", "barfoo"]` but it misses `"FOO"`.