Adding support for packer 1.5.4

* Updated to packer 1.5.4 from 1.5.0
* Updated circleci golang image

.circleci/config.yml

@@ -7,7 +7,7 @@ executors:
     working_directory: ~/packer-provisioner-serverspec
   golang:
     docker:
-      - image: circleci/golang:1.13.1
+      - image: circleci/golang:1.13.8
     working_directory: ~/packer-provisioner-serverspec
     environment:
       ALPINE_VERSION: '3.10'
@@ -16,7 +16,7 @@ executors:
       - image: circleci/ruby:2.5.5
     working_directory: ~/packer-provisioner-serverspec
     environment:
-      PACKER_VERSION: '1.5.0'
+      PACKER_VERSION: '1.5.4'
       HASHI_KEY_URL: 'https://keybase.io/hashicorp/key.asc'
 jobs:
   build_provisioner:

go.mod

@@ -1,10 +1,10 @@
 module github.com/unifio/packer-provisioner-serverspec
 
 require (
-	github.com/hashicorp/hcl/v2 v2.0.0
-	github.com/hashicorp/packer v1.5.0
-	github.com/zclconf/go-cty v1.1.2-0.20191126233707-f0f7fd24c4af
-	golang.org/x/crypto v0.0.0-20191202143827-86a70503ff7e
+	github.com/hashicorp/hcl/v2 v2.3.0
+	github.com/hashicorp/packer v1.5.4
+	github.com/zclconf/go-cty v1.2.1
+	golang.org/x/crypto v0.0.0-20200117160349-530e935923ad
 )
 
 replace git.apache.org/thrift.git => github.com/apache/thrift v0.0.0-20180902110319-2566ecd5d999