[add] bumping circleci go images to 1.12. enforcing go modules usage on makefile

Author: filipecosta90

.circleci/config.yml

@@ -45,7 +45,7 @@ jobs:
 
   build: # test with redisearch:edge
     docker:
-      - image: circleci/golang:1.9
+      - image: circleci/golang:1.12
       - image: redislabs/redisearch:edge
 
     working_directory: /go/src/github.com/RediSearch/redisearch-go
@@ -57,7 +57,7 @@ jobs:
 
   build_nightly: # test nightly with redisearch:edge
     docker:
-      - image: circleci/golang:1.9
+      - image: circleci/golang:1.12
       - image: redislabs/redisearch:edge
 
     working_directory: /go/src/github.com/RediSearch/redisearch-go

Makefile

@@ -1,5 +1,6 @@
 # Go parameters
-GOCMD=go
+GOCMD=GO111MODULE=on go
+
 GOBUILD=$(GOCMD) build
 GOINSTALL=$(GOCMD) install
 GOCLEAN=$(GOCMD) clean