Update to amber v0.6.7 (#3271)

frameworks/Crystal/amber/shard.lock

@@ -2,7 +2,7 @@ version: 1.0
 shards:
   amber:
     github: amberframework/amber
-    version: 0.6.5
+    version: 0.6.7
 
   callback:
     github: mosop/callback

frameworks/Crystal/amber/shard.yml

@@ -13,7 +13,7 @@ targets:
 dependencies:
   amber:
     github: amberframework/amber
-    version: 0.6.5
+    version: 0.6.7
 
   granite_orm:
     github: amberframework/granite-orm