Update golang:1.26-alpine Docker digest to 91eda97

Author: renovate[bot]

stacks/flow.Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1.23@sha256:2780b5c3bab67f1f76c781860de469442999ed1a0d7992a5efdf2cffc0e3d769
 
-FROM golang:1.26-alpine@sha256:f85330846cde1e57ca9ec309382da3b8e6ae3ab943d2739500e08c86393a21b1 AS builder
+FROM golang:1.26-alpine@sha256:91eda9776261207ea25fd06b5b7fed8d397dd2c0a283e77f2ab6e91bfa71079d AS builder
 # Allow build flags to be passed in at build time, for example debug flags
 ARG DEBUG_BUILD
 ENV DEBUG_BUILD=${DEBUG_BUILD}