Adding the new thread pool adjustment reason (lack of this was causing exceptions when discovered) (#70)

Co-authored-by: James Luck <[email protected]>

Author: djluck

src/prometheus-net.DotNetRuntime/EventListening/Sources/DotNetRuntimeEventSource.cs

@@ -221,6 +221,7 @@ public enum ThreadAdjustmentReason : uint
             Stabilizing,
             Starvation,
             ThreadTimedOut,
+            CooperativeBlocking
         }
     }
 }