prep 8.4.0

Author: JoernBerkefeld

.github/ISSUE_TEMPLATE/bug.yml

@@ -39,6 +39,7 @@ body:
           label: Version
           description: What version of our software are you running? (mcdev --version)
           options:
+              - 8.4.0
               - 8.3.1
               - 8.3.0
               - 8.2.1

test/mockRoot/.mcdevrc.json

@@ -178,5 +178,5 @@
             "verification"
         ]
     },
-    "version": "8.3.1"
+    "version": "8.4.0"
 }