Add more metadata to Chart.yaml (apache#15866)

- Adds more metadata like `appVersion`, `home`, `maintainers`, `sources` etc
- Remove `tests` from `helm package`

Author: kaxil

chart/.helmignore

@@ -37,3 +37,6 @@
 .idea/
 *.tmproj
 bin
+
+# We do not want to include our Python Helm Chart Unit test files
+tests

chart/Chart.yaml

@@ -20,7 +20,18 @@
 apiVersion: v1
 name: airflow
 version: 1.0.0
-description: Helm chart to deploy Apache Airflow
+appVersion: 2.0.2
+description: Helm chart to deploy Apache Airflow, a platform to
+  programmatically author, schedule, and monitor workflows
+home: https://airflow.apache.org/
 icon: https://airflow.apache.org/docs/apache-airflow/stable/_images/pin_large.png
 keywords:
+  - apache
   - airflow
+  - workflow
+  - scheduler
+maintainers:
+  - email: [email protected]
+    name: Apache Airflow PMC
+sources:
+  - https://github.com/apache/airflow