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

Bumps golang from 1.26.2-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>

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:1.26.2-bookworm@sha256:4f4ab2c90005e7e63cb631f0b4427f05422f241622ee3ec4727cc5febbf83e34 AS golang-base
+FROM golang:1.26.3-bookworm@sha256:b09e568dcf2a1ff3ce09a230ea234193fc014dc195472fe63316e50238453d96 AS golang-base
 
 
 FROM golang-base AS golang-control-plane-builder