Merge #124

124: Standardize health method  r=curquiza a=alallema

**Description**
Checking that method `health()` return `{'status': 'available'}` and added `is_healthy()` method who return boolean value

**Issue related**
meilisearch/integration-guides#55

**Some points of concern**
- I let `Health` struct like it was:
```rust
#[derive(Deserialize)]
pub struct Health {
    pub status: String,
}
```
but I see we could write it this way too:
```rust
#[derive(Deserialize)]
#[serde(tag="status")]
pub enum Health {
    #[serde(rename="available")]
    Available
}
```
 That's means API should return `'available'` and this could lead to more maintenance but it seemed to be more accurate.

Co-authored-by: alallema <[email protected]>
Co-authored-by: Amélie <[email protected]>

Author: bors[bot]

src/client.rs

@@ -176,7 +176,7 @@ impl<'a> Client<'a> {
     /// # Example
     ///
     /// ```
-    /// # use meilisearch_sdk::{client::*, indexes::*, errors::{Error, ErrorCode}};
+    /// # use meilisearch_sdk::{client::*, errors::{Error, ErrorCode}};
     /// #
     /// # futures::executor::block_on(async move {
     /// let client = Client::new("http://localhost:7700", "masterKey");
@@ -193,6 +193,27 @@ impl<'a> Client<'a> {
         .await
     }
 
+    /// Get health of MeiliSearch server, return true or false.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use meilisearch_sdk::client::*;
+    /// #
+    /// # futures::executor::block_on(async move {
+    /// let client = Client::new("http://localhost:7700", "masterKey");
+    /// let health = client.is_healthy().await;
+    /// assert_eq!(health, true);
+    /// # });
+    /// ```
+    pub async fn is_healthy(&self) -> bool {
+        if let Ok(health) = self.health().await {
+            health.status.as_str() == "available"
+        } else {
+            false
+        }
+    }
+
     /// Get the private and public key.
     ///
     /// # Example