Update build image to Go 1.22 (#285)

This commit updates the build image to Go 1.22 as the docker build
was failing on Go 1.16.

Author: grobinson-grafana

cmd/benchtool/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.16.8-stretch as build
+FROM golang:1.22 as build
 ARG GOARCH="amd64"
 COPY . /build_dir
 WORKDIR /build_dir

cmd/cortextool/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.16.8-stretch as build
+FROM golang:1.22 as build
 ARG GOARCH="amd64"
 COPY . /build_dir
 WORKDIR /build_dir

cmd/e2ealerting/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.16.8-stretch as build
+FROM golang:1.22 as build
 ARG GOARCH="amd64"
 COPY . /build_dir
 WORKDIR /build_dir

cmd/logtool/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.16.8-stretch as build
+FROM golang:1.22 as build
 ARG GOARCH="amd64"
 COPY . /build_dir
 WORKDIR /build_dir