Include the tags field migration.

web/modules/custom/agaric_migration/migrations/agaric_blog.yml

@@ -2,7 +2,7 @@ id: agaric_blog
 migration_group: agaric
 label: Agaric Blog
 source:
-  plugin: d7_node
+  plugin: agaric_node
   node_type: blog
 destination:
   plugin: entity:node
@@ -61,6 +61,18 @@ process:
     plugin: migration_lookup
     source: node_uid
     migration: agaric_people
+  field_tags:
+    plugin: sub_process
+    source: field_tags_names
+    process:
+      target_id:
+      - plugin: entity_generate
+        source: name
+        value_key: name
+        bundle_key: vid
+        bundle: tags
+        entity_type: taxonomy_term
+        ignore_case: true
 migration_dependencies:
   required:
     - agaric_people