Temporarily fix bitnami index problem

We started to experience "Internal Error" when installing
Helm chart and apperently bitnami "solved" the problem by
removing from their index software older than 6 months(!).

This makes our CI fail but It is much worse. This
renders all our charts useless for people to install
This is terribly wrong, and I raised this in the issue
here:

bitnami/charts#10539 (comment)

chart/Chart.yaml

@@ -35,7 +35,13 @@ keywords:
 dependencies:
   - name: postgresql
     version: 10.5.3
-    repository: "https://raw.githubusercontent.com/bitnami/charts/index/bitnami"
+    # In order to react to a sudden, totally breaking change by bitnami in
+    # https://github.com/bitnami/charts/issues/10539
+    # we need to use the version of index from just before the change. However we hope
+    # it is only temporary change as it breaks all our charts we released so far
+    # see comment here https://github.com/bitnami/charts/issues/10539#issuecomment-1144869092
+    repository: >
+      https://raw.githubusercontent.com/bitnami/charts/eb5f9a9513d987b519f0ecd732e7031241c50328/bitnami
     condition: postgresql.enabled
 maintainers:
   - email: dev@airflow.apache.org