Merge pull request #367 from puppetlabs/CONT-782-add_puppet8_support

(CONT-782) - add puppet 8 support/Drop puppet 6 support

Author: david22swan

.devcontainer/devcontainer.json

@@ -5,7 +5,7 @@
 	"settings": {
 		"terminal.integrated.profiles.linux": {
 			"bash": {
-				"path": "bash",
+				"path": "bash"
 			}
 		}
 	},

.fixtures.yml

@@ -1,14 +1,13 @@
 fixtures:
-  forge_modules:
-    dism: 'puppetlabs/dism'
+  forge_modules:    
     pwshlib: 'puppetlabs/pwshlib'
     ruby_task_helper: 'puppetlabs/ruby_task_helper'
   repositories:
     stdlib: 'https://github.com/puppetlabs/puppetlabs-stdlib.git'
     facts: 'https://github.com/puppetlabs/puppetlabs-facts.git'
     puppet_agent:
       repo: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
-      ref: v4.12.1
+      ref: v4.13.0
     provision: 'https://github.com/puppetlabs/provision.git'
   symlinks:
     iis: "#{source_dir}"