chore(deps): update golang docker tag to v1.26 (#27)

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

Author: renovate[bot]

Dockerfile

@@ -1,7 +1,7 @@
 # Multi-stage Dockerfile for Echo Server (Golang/Fiber)
 
 ## Stage 1: Build the Go binary
-FROM golang:1.25-alpine3.23 AS build
+FROM golang:1.26-alpine3.23 AS build
 
 # Install build dependencies
 RUN apk add --no-cache git