Build process change (#1606)

* fix: GOFLAGS changed so that the build process uses the vendor directory;

* fix: a redundant makefile line removed, prevents local cache build-up;

Author: yakom

Makefile

@@ -66,13 +66,12 @@ K3D_HELPER_VERSION ?=
 # Go options
 GO        ?= go
 GOENVPATH := $(shell go env GOPATH)
-PKG       := $(shell go work vendor)
 TAGS      :=
 TESTS     := ./...
 TESTFLAGS :=
 LDFLAGS   := -w -s -X github.com/k3d-io/k3d/v5/version.Version=${GIT_TAG} -X github.com/k3d-io/k3d/v5/version.K3sVersion=${K3S_TAG}
 GCFLAGS   :=
-GOFLAGS   := -mod=readonly
+GOFLAGS   := -mod=vendor
 BINDIR    := $(CURDIR)/bin
 BINARIES  := k3d