feat: improve sesh version during local build (#141)

sets the sesh -v flag version according to the latest git tag

Makefile

@@ -1,7 +1,9 @@
 .PHONY: test build
 
+BUILD_FLAGS="-X 'main.version=`git describe --tags --abbrev=0`'"
+
 test:
 	go test -cover -bench=. -benchmem -race ./... -coverprofile=coverage.out
 
 build: 
-	go build -o $(shell echo $$GOPATH)/bin/sesh-dev
+	@go build -ldflags ${BUILD_FLAGS} -o $(shell echo $$GOPATH)/bin/sesh-dev