Fix builder docker image

Problem: The builder docker image was out of date and didn't copy the correct files.
Solution: Copy the whole directory and run the make command to ensure everything is always in sync.

Author: sjberman

build/Dockerfile

@@ -4,15 +4,10 @@ ARG VERSION
 ARG GIT_COMMIT
 ARG DATE
 
-WORKDIR /go/src/github.com/nginxinc/nginx-kubernetes-gateway/cmd/gateway
+WORKDIR /go/src/github.com/nginxinc/nginx-kubernetes-gateway
 
-COPY go.mod go.sum /go/src/github.com/nginxinc/nginx-kubernetes-gateway
-RUN go mod download
-
-COPY cmd /go/src/github.com/nginxinc/nginx-kubernetes-gateway/cmd
-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 .
+COPY . /go/src/github.com/nginxinc/nginx-kubernetes-gateway
+RUN make build
 
 FROM alpine:3.18 as capabilizer
 RUN apk add --no-cache libcap
@@ -22,7 +17,7 @@ COPY ./build/out/gateway /usr/bin/
 RUN setcap 'cap_kill=+ep' /usr/bin/gateway
 
 FROM capabilizer as container-capabilizer
-COPY --from=builder /go/src/github.com/nginxinc/nginx-kubernetes-gateway/cmd/gateway/gateway /usr/bin/
+COPY --from=builder /go/src/github.com/nginxinc/nginx-kubernetes-gateway/build/out/gateway /usr/bin/
 RUN setcap 'cap_kill=+ep' /usr/bin/gateway
 
 FROM capabilizer as goreleaser-capabilizer