Bump version to v2.2.1-dev

backend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mempool-backend",
-  "version": "2.2.0",
+  "version": "2.2.1-dev",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "mempool-backend",
-      "version": "2.2.0",
+      "version": "2.2.1-dev",
       "license": "GNU Affero General Public License v3.0",
       "dependencies": {
         "@mempool/bitcoin": "^3.0.2",