Mark project as deprecated (#108)

README.md

@@ -1,3 +1,11 @@
+# DEPRECATED
+
+> [!IMPORTANT]
+> This library has been deprecated in favor of [official support](https://github.com/DataDog/dd-sdk-kotlin-multiplatform).
+
+<details>
+<summary>Previous README</summary>
+
 # Datadog KMP (Kotlin Multiplatform)
 
 Datadog KMP provides a unified [Datadog] API for use in Kotlin multiplatform projects.
@@ -45,6 +53,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 ```
+</details>
 
 
 [Datadog]: https://www.datadoghq.com/