add attrs to downstream, fix jsonschema label ci trigger

.github/workflows/ci.yml

@@ -12,6 +12,12 @@ on:
     tags:
       - '*'
   pull_request:
+    # We also want this workflow triggered if the `jsonschema` label is
+    # added or present when PR is updated
+    types:
+      - synchronize
+      - labeled
+
 
 # Only cancel in-progress jobs or runs for the current workflow
 #   This cancels the already triggered workflows for a specific PR without canceling

requirements-dev.txt

@@ -1,6 +1,7 @@
 git+https://github.com/asdf-format/asdf-standard
 git+https://github.com/asdf-format/asdf-transform-schemas
 git+https://github.com/yaml/pyyaml.git
+git+https://github.com/python-attrs/attrs
 
 numpy>=0.0.dev0
 # although we don't use scipy, we include it here so that any dependency