Two fixes: (saleor#9296)

* We don't rely on composer.json to determine previous version (and in new release-it it deesn't gracefully fallback to CLI prompt)
 * Version change in package.json is handled bym npm itself (and leaving it for bumper is causing npm to fail with: ERR Version not changed)

Author: magul

.release-it.json

@@ -9,9 +9,7 @@
   },
   "plugins": {
     "@release-it/bumper": {
-      "in": "composer.json",
       "out": [
-        "package.json",
         {
           "file": "pyproject.toml",
           "path": "tool.poetry.version"