cmd/relui: upgrade to Go 1.18 and Debian 11

Updates golang/go#47407

Change-Id: I4a07a18e817ff5deac8de97779d2957396e053f7
Reviewed-on: https://go-review.googlesource.com/c/build/+/410235
Run-TryBot: Alex Rakoczy <alex@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
diff --git a/cmd/relui/Dockerfile b/cmd/relui/Dockerfile
index ad3b0bf..854eef5 100644
--- a/cmd/relui/Dockerfile
+++ b/cmd/relui/Dockerfile
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-FROM golang:1.17 AS build
+FROM golang:1.18 AS build
 
 COPY go.mod /app/go.mod
 COPY go.sum /app/go.sum
@@ -15,7 +15,7 @@
 
 RUN go build golang.org/x/build/cmd/relui
 
-FROM marketplace.gcr.io/google/debian10:latest
+FROM marketplace.gcr.io/google/debian11:latest
 
 RUN apt-get update && apt-get install -y \
 	--no-install-recommends \
diff --git a/cmd/relui/Dockerfile.test b/cmd/relui/Dockerfile.test
index 037fc8a..50365b1 100644
--- a/cmd/relui/Dockerfile.test
+++ b/cmd/relui/Dockerfile.test
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-FROM golang:1.17 AS build
+FROM golang:1.18 AS build
 
 COPY go.mod /app/go.mod
 COPY go.sum /app/go.sum