improve release instructions

adds instructions to bump widget view/model version attrs on release

{{cookiecutter.github_project_name}}/RELEASE.md

@@ -1,22 +1,25 @@
-- To release a new version of {{ cookiecutter.python_package_name  }} on PyPI:
+To release a new version of the {{ cookiecutter.python_package_name  }} Python library on PyPI:
 
-Update _version.py (set release version, remove 'dev')
-git add the _version.py file and git commit
-`python setup.py sdist upload`
-`python setup.py bdist_wheel upload`
-`git tag -a X.X.X -m 'comment'`
-Update _version.py (add 'dev' and increment minor)
-git add and git commit
-git push
-git push --tags
+- Update `_version.py` (set release version, remove 'dev')
+- git add the `_version.py` file and git commit
+- ```
+  python setup.py sdist bdist_wheel
+  twine upload dist/*
+  git tag -a X.X.X -m 'comment'
+  git add and git commit
+  git push
+  git push --tags
+  ```
 
-- To release a new version of {{ cookiecutter.npm_package_name }} on NPM:
+To release a new version of {{ cookiecutter.npm_package_name }} on NPM:
 
-Update `js/package.json` with new npm package version
-
-```
-# clean out the `dist` and `node_modules` directories
-git clean -fdx
-npm install
-npm publish
-```
+- Update `js/package.json` with new npm package version
+- Update the following attributes on your widget implementations in the Python and Javascript packages:
+  - `_view_module_version`
+  - `_model_module_version`
+- ```
+  # clean out the `dist` and `node_modules` directories
+  git clean -fdx
+  npm install
+  npm publish
+  ```