ci(schema-diff): Generate one file per constraint (#3082)

This yeilds a better diff when constraints are changed.

.github/workflows/schema-diff.yml

@@ -74,8 +74,8 @@ jobs:
           #### Indexes
           $(getdiff .schema-diff/indexes.diff)
 
-          #### Post Data
-          $(getdiff .schema-diff/post_data.diff)
+          #### Constraints
+          $(getdiff .schema-diff/constraints.diff)
           EOF
 
           # Parse it through jq to build a valid json object.