Merge pull request #1003 from aws-powertools/version-for-release

chore: Update Metrics version to 2.2.0

Author: hjgraca

version.json

@@ -1,7 +1,7 @@
 {
   "Core": {
     "Logging": "2.0.2",
-    "Metrics": "2.1.1",
+    "Metrics": "2.2.0",
     "Tracing": "1.6.2",
     "Metrics.AspNetCore": "0.1.0"
   },