Update alpine Docker tag to v3.20 (#239)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| alpine | final | minor | `3.19` -> `3.20` |

---
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

build/Dockerfile

@@ -28,7 +28,7 @@ RUN make build-binary generate-notice.txt
 #
 # package binaries in a lighter final image
 #
-FROM alpine:3.19
+FROM alpine:3.20
 
 ARG IMAGE_TAG
 ENV IMAGE_TAG=$IMAGE_TAG