title: Package is not in GOROOT
body: <p><strong>main.go:5:2: package greetings is not in GOROOT (C:\Program Files\Go\src\greetings)</strong></p>
  <p>I am reading Head first go and it was written to create folder in c:/users/username/go/src/packagename and c:/users/username/go/src/project_name</p>
  <p>when i try to run</p>
  <p><code>go run main.go</code> from project_name folder, i got the following error.
  <code>main.go:5:2: package greetings is not in GOROOT (C:\Program Files\Go\src\greetings)</code></p>
  <pre><code>C:\Users\agriz&gt;go env
  set GO111MODULE=on
  set GOARCH=amd64
  set GOBIN=
  set GOCACHE=C:\Users\agriz\AppData\Local\go-build
  set GOENV=C:\Users\agriz\AppData\Roaming\go\env
  set GOEXE=.exe
  set GOFLAGS=
  set GOHOSTARCH=amd64
  set GOHOSTOS=windows
  set GOINSECURE=
  set GOMODCACHE=C:\Users\agriz\go\pkg\mod
  set GONOPROXY=
  set GONOSUMDB=
  set GOOS=windows
  set GOPATH=C:\Users\agriz\go
  set GOPRIVATE=
  set GOPROXY=https://proxy.golang.org,direct
  set GOROOT=C:\Program Files\Go
  set GOSUMDB=sum.golang.org
  set GOTMPDIR=
  set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
  set GOVCS=
  set GOVERSION=go1.16.7
  set GCCGO=gccgo
  set AR=ar
  set CC=gcc
  set CXX=g++
  set CGO_ENABLED=1
  set GOMOD=NUL
  set CGO_CFLAGS=-g -O2
  set CGO_CPPFLAGS=
  set CGO_CXXFLAGS=-g -O2
  set CGO_FFLAGS=-g -O2
  set CGO_LDFLAGS=-g -O2
  set PKG_CONFIG=pkg-config
  set GOGCCFLAGS=-m64 -mthreads -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\agriz\AppData\Local\Temp\go-build2047492330=/tmp/go-build -gno-record-gcc-switches
  </code></pre>
  <p>I dont want to keep the code in c drive. I want to run codes from D:/ is that possible? How can i do that?</p>