chart: 0.2.0 artifacthub changelog

Replace stale "Initial chart release" entry with actual 0.2.0 changes
(OTel collector stack bump to v0.150, config corrections, appVersion 0.2.0).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: prathamesh-sonpatki

deploy/helm/l9gpu/Chart.yaml

@@ -36,5 +36,9 @@ annotations:
     - name: Metrics reference
       url: https://github.com/last9/gpu-telemetry/blob/main/docs/METRICS.md
   artifacthub.io/changes: |
-    - kind: added
-      description: Initial chart release
+    - kind: changed
+      description: Bump OpenTelemetry Collector stack to v0.150
+    - kind: fixed
+      description: Collector builder and example config corrections
+    - kind: changed
+      description: Chart appVersion bumped to 0.2.0