chore(helm): update image ghcr.io/linuxserver/piwigo digest to a9e8f9f (#40225)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
|
[ghcr.io/linuxserver/piwigo](https://redirect.github.com/linuxserver/docker-piwigo/packages)
([source](https://redirect.github.com/linuxserver/docker-piwigo)) |
digest | `0d77966` -> `a9e8f9f` |

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charts/stable/piwigo/values.yaml

@@ -1,7 +1,7 @@
 image:
   repository: ghcr.io/linuxserver/piwigo
   pullPolicy: IfNotPresent
-  tag: 15.6.0@sha256:0d779666d9c98754350e157f59def36335af49b709c4fa1dd8097cb6c2aa9ca8
+  tag: 15.6.0@sha256:a9e8f9fb64acacfeb33966b298cccaf5b711b62c79466b3058898b2163233970
 securityContext:
   container:
     runAsNonRoot: false