Docker: fix docker builds

Signed-off-by: Valery Piashchynski <piashchynski.valery@gmail.com>

Dockerfile

@@ -1,6 +1,6 @@
 # https://docs.docker.com/buildx/working-with-buildx/
 # TARGETPLATFORM if not empty OR linux/amd64 by default
-FROM --platform=${TARGETPLATFORM:-linux/amd64} golang:1.18.4-alpine as builder
+FROM --platform=${TARGETPLATFORM:-linux/amd64} golang:1.18-alpine as builder
 
 # app version and build date must be passed during image building (version without any prefix).
 # e.g.: `docker build --build-arg "APP_VERSION=1.2.3" --build-arg "BUILD_TIME=$(date +%FT%T%z)" .`
@@ -19,9 +19,10 @@ ENV LDFLAGS="-s \
 RUN set -x
 RUN go mod download
 RUN go mod tidy -go 1.18
-RUN CGO_ENABLED=0 go build -trimpath -ldflags "$LDFLAGS" -o ./velox ./vx
 
-FROM --platform=${TARGETPLATFORM:-linux/amd64} golang:1.18.4-alpine
+RUN CGO_ENABLED=0 go build -trimpath -ldflags "$LDFLAGS" -o ./velox ./cmd/vx
+
+FROM --platform=${TARGETPLATFORM:-linux/amd64} golang:1.18-alpine
 
 # use same build arguments for image labels
 ARG APP_VERSION="undefined"