Fix the example for atomic.run in LABELS.md

The sample for 'atomic.run' lable has been wrongly typed as
'atomic.type'. Correct the sample to relfect the correct lable
name.

Closes: #127
Approved by: giuseppe

LABELS.md

@@ -26,7 +26,7 @@ and then removed.
 
 ### Example
 ```
-atomic.type="once"
+atomic.run="once"
 ```