add changeset for group by

Author: angrykoala

.changeset/petite-lizards-reply.md

@@ -0,0 +1,30 @@
+---
+"@neo4j/graphql": minor
+---
+
+Add `groupBy` fields in connections for grouping results.
+
+These can be enabled with the `@groupBy` directive:
+
+```graphql
+type Movie {
+    title: String!
+    year: Int! @groupBy
+}
+```
+
+This enables queries such as:
+
+```graphql
+moviesConnection {
+    groupBy(fields: {year: true}) {
+        edges {
+            node {
+                title
+            }
+        }
+    }
+}
+```
+
+Which returns the movies, grouped by `year`