chore(deps): update docker.io/alpine docker tag to v3.20 (#140)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| docker.io/alpine | final | minor | `3.19` -> `3.20` |

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Reviewed-on: #140
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Co-committed-by: Renovator Bot <renovator@rknet.org>

Containerfile.multiarch

@@ -1,4 +1,4 @@
-FROM docker.io/alpine:3.19@sha256:c5b1261d6d3e43071626931fc004f70149baeba2c8ec672bd4f27761f8e1ad6b
+FROM docker.io/alpine:3.20@sha256:77726ef6b57ddf65bb551896826ec38bc3e53f75cdde31354fbffb4f25238ebd
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"