Update golang Docker tag to v1.26.0

| datasource | package | from   | to     |
| ---------- | ------- | ------ | ------ |
| docker     | golang  | 1.25.6 | 1.26.0 |


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

Author: renovate[bot]

build/Dockerfile

@@ -1,5 +1,5 @@
 # syntax=docker/dockerfile:1.20
-FROM golang:1.25.6 AS builder
+FROM golang:1.26.0 AS builder
 ARG VERSION
 ARG TARGETARCH