Bump alpine from 3.15 to 3.16.1 in /build

Bumps alpine from 3.15 to 3.16.1.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

build/Dockerfile

@@ -13,7 +13,7 @@ COPY internal /go/src/github.com/nginxinc/nginx-kubernetes-gateway/internal
 COPY pkg /go/src/github.com/nginxinc/nginx-kubernetes-gateway/pkg
 RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -a -ldflags "-s -w -X main.version=${VERSION} -X main.commit=${GIT_COMMIT} -X main.date=${DATE}" -o gateway .
 
-FROM alpine:3.15 as capabilizer
+FROM alpine:3.16.1 as capabilizer
 RUN apk add --no-cache libcap
 
 FROM capabilizer as local-capabilizer