docs: change from detecting version to since tag (#13127)

* update everything from version to since

* update events

* regenerate oas

www/utils/generated/events-output.json

@@ -44,7 +44,7 @@
     "workflows": [
       "transferCartCustomerWorkflow"
     ],
-    "version": "2.8.0",
+    "since": "2.8.0",
     "deprecated": false
   },
   {
@@ -227,7 +227,7 @@
     "workflows": [
       "requestOrderEditRequestWorkflow"
     ],
-    "version": "2.8.0",
+    "since": "2.8.0",
     "deprecated": false
   },
   {
@@ -239,7 +239,7 @@
     "workflows": [
       "confirmOrderEditRequestWorkflow"
     ],
-    "version": "2.8.0",
+    "since": "2.8.0",
     "deprecated": false
   },
   {
@@ -251,7 +251,7 @@
     "workflows": [
       "cancelBeginOrderEditWorkflow"
     ],
-    "version": "2.8.0",
+    "since": "2.8.0",
     "deprecated": false
   },
   {