make the only/except example & test consistent

command/test-fixtures/build-only/template.pkr.hcl

@@ -42,13 +42,13 @@ build {
   }
 
   post-processor "shell-local" {
-    only = ["vanilla"]
+    only = ["sources.file.vanilla"]
     name = "tomato"
     inline = [ "echo apple > tomato.txt" ]
   }
 
   post-processor "shell-local" {
-    only = ["chocolate"]
+    only = ["sources.file.chocolate"]
     inline = [ "echo apple > unnamed.txt" ]
   }
 }

hcl2template/testdata/build/post-processor_onlyexcept.pkr.hcl

@@ -7,10 +7,10 @@ build {
     ]
 
     post-processor "amazon-import" {
-        only = ["virtualbox-iso.ubuntu-1204"]
+        only = ["source.virtualbox-iso.ubuntu-1204"]
     }
     post-processor "manifest" {
-        except = ["virtualbox-iso.ubuntu-1204"]
+        except = ["source.virtualbox-iso.ubuntu-1204"]
     }
 }
 

hcl2template/testdata/build/provisioner_onlyexcept.pkr.hcl

@@ -7,10 +7,10 @@ build {
     ]
 
     provisioner "shell" {
-        only = ["virtualbox-iso.ubuntu-1204"]
+        only = ["source.virtualbox-iso.ubuntu-1204"]
     }
     provisioner "file" {
-        except = ["virtualbox-iso.ubuntu-1204"]
+        except = ["source.virtualbox-iso.ubuntu-1204"]
     }
 }