build(deps): bump golang in /shared/golang

Bumps golang from 1.25.5-bookworm to 1.25.6-bookworm.

---
updated-dependencies:
- dependency-name: golang
  dependency-version: 1.25.6-bookworm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

shared/golang/Dockerfile

@@ -3,7 +3,7 @@ RUN rm -f /etc/apt/apt.conf.d/docker-clean \
     && echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' | tee /etc/apt/apt.conf.d/keep-cache
 
 
-FROM golang:1.25.5-bookworm@sha256:2c7c65601b020ee79db4c1a32ebee0bf3d6b298969ec683e24fcbea29305f10e AS golang-base
+FROM golang:1.25.6-bookworm@sha256:2f768d462dbffbb0f0b3a5171009f162945b086f326e0b2a8fd5d29c3219ff14 AS golang-base
 
 
 FROM golang-base AS golang-control-plane-builder