Build appends .exe to file name for non-Windows builds

[hdm]

Description

buffalo build appends ".exe" to the outfile file name on Windows, even when building non-Windows binaries. This is the opposite problem of #623.

A workaround for build scripts is to generate a .exe and then explicitly rename it afterwards.

Steps to Reproduce the Problem

set GOOS=linux
set GOARCH=amd64
buffalo build -o test.bin

This results in test.bin.exe being created. This wasn't the case with 0.13.x builds.

Expected Behavior

The generated file matches the -o parameter of buffalo build.

Actual Behavior

The wrong file extension is applied.

Info

Please run buffalo info and paste the information below where it says "PASTE_HERE".

### Buffalo Version
v0.14.0-beta.2

### App Information
Pwd=C:\Users\Developer\go\src\github.com\hdm\myapp-console
Root=C:\Users\Developer\go\src\github.com\hdm\myapp-console
GoPath=C:\Users\Developer\go
PackagePkg=github.com/hdm/myapp-console
ActionsPkg=github.com/hdm/myapp-console/actions
ModelsPkg=github.com/hdm/myapp-console/models
GriftsPkg=github.com/hdm/myapp-console/grifts
WithModules=false
Name=myapp-console
Bin=bin\myapp-console.exe
VCS=git
WithPop=true
WithSQLite=false
WithDep=true
WithWebpack=true
WithNodeJs=true
WithYarn=true
WithDocker=false
WithGrifts=true
AsWeb=true
AsAPI=false

### Go Version
go version go1.11.4 windows/amd64

### Go Env
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Developer\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:\Users\Developer\go
set GOPROXY=
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
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 -fmessage-length=0 -fdebug-prefix-map=C:\Users\DEVELO~1\AppData\Local\Temp\go-build761009278=/tmp/go-build -gno-record-gcc-switches

### Node Version
v10.15.0

### NPM Version
6.4.1

### Yarn Version
1.12.3

### PostgreSQL Version
PostgreSQL Not Found

### MySQL Version
MySQL Not Found

### SQLite Version
3.7.17 2013-05-20 00:56:22 118a3b35693b134d56ebd780123b7fd6f1497668

### Dep Version
dep:
 version     : devel
 build date  : 
 git hash    : 
 go version  : go1.11.1
 go compiler : gc
 platform    : windows/amd64
 features    : ImportDuringSolve=false

### Dep Status
Gopkg.lock is out of sync with imports and/or Gopkg.toml. Run `dep check` for details.
PROJECT  MISSING PACKAGES
input-digest mismatch