chore(backrest): pin image docker.io/garethgeorge/backrest digest to 1308397 (#43329)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
|
[docker.io/garethgeorge/backrest](https://redirect.github.com/garethgeorge/backrest)
| pinDigest | -> `1308397` |

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charts/incubator/backrest/values.yaml

@@ -1,6 +1,6 @@
 image:
   repository: docker.io/garethgeorge/backrest
-  tag: v1.10.1
+  tag: v1.10.1@sha256:1308397161321b3c5aeca8acc6bf26eccb990df385f2532d3ce0eaa8b483dedf
   pullPolicy: IfNotPresent
 
 service: