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

Bumps golang from 1.25.10-bookworm to 1.26.3-bookworm.

---
updated-dependencies:
- dependency-name: golang
  dependency-version: 1.26.3-bookworm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: phlax <454682+phlax@users.noreply.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:1.25.10-bookworm@sha256:e3a54b77385b4f8a31c1db4d12429ffb3718ea76865731a787c497755d409547 AS golang-base
+FROM golang:1.26.3-bookworm@sha256:252599aeb51ad60b83e4d8821802068127c528c707cb7dd7afd93be057c6011c AS golang-base
 
 
 FROM golang-base AS golang-control-plane-builder