Add "from" field to CreateDraftRequest (#233)

The SDK should allow setting the "from" address. This was a feature in
v2 and is available in the v3 API. Many accounts have "from" aliases or
valid alternate "from" addresses that can be used when sending emails.

# License
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Co-authored-by: Mostafa Rashed <[email protected]>

src/main/kotlin/com/nylas/models/CreateDraftRequest.kt

@@ -6,6 +6,11 @@ import com.squareup.moshi.Json
  * Class representing a request to create a draft.
  */
 data class CreateDraftRequest(
+  /**
+   * From address. (Optional) If not provided, the default address will be used.
+   */
+  @Json(name = "from")
+  val from: List<EmailName>? = null,
   /**
    * An array of message recipients.
    */
@@ -72,6 +77,7 @@ data class CreateDraftRequest(
    * Builder for [CreateDraftRequest].
    */
   class Builder {
+    private var from: List<EmailName>? = null
     private var to: List<EmailName>? = null
     private var bcc: List<EmailName>? = null
     private var cc: List<EmailName>? = null
@@ -85,6 +91,13 @@ data class CreateDraftRequest(
     private var trackingOptions: TrackingOptions? = null
     private var customHeaders: List<CustomHeader>? = null
 
+    /**
+     * Sets the from address.
+     * @param from The from address.
+     * @return The builder.
+     */
+    fun from(from: List<EmailName>?) = apply { this.from = from }
+
     /**
      * Sets the recipients.
      * @param to The recipients.
@@ -176,6 +189,7 @@ data class CreateDraftRequest(
      */
     fun build() =
       CreateDraftRequest(
+        from,
         to,
         bcc,
         cc,