Improve Makefile (#203)

* Improve Makefile

* Remove hardcoded references to GOOS and GOARCH
* Use `go install` for the `install` target
* Unify parentheses versus curly braces
* Abstract duplicate path

* Restyled by whitespace

Co-authored-by: Restyled.io <commits@restyled.io>

Author: 0x2b3bfa0

Makefile

@@ -1,22 +1,21 @@
 HOSTNAME=github.com
 NAMESPACE=iterative
 NAME=iterative
-VERSION=0.6
-#OS_ARCH=linux_amd64
-OS_ARCH=darwin_amd64
+VERSION=0.0.0+development
+OS_ARCH=${shell go env GOOS}_${shell go env GOARCH}
 BINARY=terraform-provider-${NAME}
+INSTALL_PATH=~/.terraform.d/plugins/${HOSTNAME}/${NAMESPACE}/${NAME}/${VERSION}/${OS_ARCH}
 
 default: install
 
 build:
-	go build -o ${BINARY}
+	go build
 
-install: build
-	mkdir -p ~/.terraform.d/plugins/${HOSTNAME}/${NAMESPACE}/${NAME}/${VERSION}/${OS_ARCH}
-	mv ${BINARY} ~/.terraform.d/plugins/${HOSTNAME}/${NAMESPACE}/${NAME}/${VERSION}/${OS_ARCH}
+install:
+	GOBIN=${INSTALL_PATH} go install
 
 test:
-	go test ./... $(TESTARGS) -timeout=30s -parallel=4
+	go test ./... ${TESTARGS} -timeout=30s -parallel=4
 
 testacc:
-	TF_ACC=1 go test ./... -v $(TESTARGS) -timeout 120m
+	TF_ACC=1 go test ./... -v ${TESTARGS} -timeout 120m