ci: update release workflow for prebuilt (#3621)

Author: vbarda

Diff for: .github/workflows/release.yml

@@ -195,6 +195,10 @@ jobs:
               "$PKG_NAME==$VERSION" \
           )
 
+          if [[ "$PKG_NAME" == *prebuilt* ]]; then
+            poetry run pip install langgraph
+          fi
+
           if [[ "$PKG_NAME" == *checkpoint* || "$PKG_NAME" == *prebuilt* ]]; then
             # since checkpoint packages are namespace packages, import them with . convention
             # i.e. import langgraph.checkpoint or langgraph.checkpoint.sqlite