Update version for release

Author: christian-schlichtherle

Chart.yaml

@@ -13,4 +13,4 @@ name: synology-csi
 sources:
   - https://github.com/christian-schlichtherle/synology-csi-chart/tree/main
   - https://github.com/SynologyOpenSource/synology-csi/tree/main
-version: 0.9.8-SNAPSHOT # must be SemVer 2
+version: 0.9.8 # must be SemVer 2