Prepare to release dwds 18.0.0 (#1993)

* Prepare to release dwds

* Use dev channel to run publish

* Correctly switch to using dev SDK for publish task

* Try disabling publsh verification

* Merge with master

Author: Anna Gringauze

.github/workflows/publish.yaml

@@ -12,3 +12,5 @@
 #   publish:
 #     if: ${{ github.repository_owner == 'dart-lang' }}
 #     uses: dart-lang/ecosystem/.github/workflows/publish.yaml@main
+#     with:
+#       sdk: dev

dwds/CHANGELOG.md

@@ -1,4 +1,4 @@
-## 18.0.0-dev
+## 18.0.0
 
 - Cleanup `getObject` code for lists and maps.
   - Now works with offset `0` and `null` count.