add manifest pipeline

.drone.yml

@@ -43,3 +43,26 @@ steps:
       from_secret: docker_token
     build_args:
       - TARGETPLATFORM=linux/arm64
+
+---
+kind: pipeline
+type: docker
+name: manifest
+
+steps:
+- name: manifest
+  image: plugins/manifest
+  settings:
+    target: bbilly1/tubearchivist-test
+    template: bbilly1/tubearchivist-test:unstable-OS-ARCH
+    username:
+      from_secret: docker_username
+    password:
+      from_secret: docker_password
+    platforms:
+    - linux/amd64
+    - linux/arm64
+
+depends_on:
+- amd64
+- arm64