Add blurhash field to ContentAttachment data

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/content/ContentAttachmentData.kt

@@ -37,7 +37,8 @@ data class ContentAttachmentData(
         val queryUri: Uri,
         val mimeType: String?,
         val type: Type,
-        val waveform: List<Int>? = null
+        val waveform: List<Int>? = null,
+        val blurHash: String? = null
 ) : Parcelable {
 
     @JsonClass(generateAdapter = false)