Update release instructions to use new build mechanism (#241)

Author: ccordoba12

RELEASE.md

@@ -12,8 +12,10 @@
 2. Close milestone on GitHub
 3. git clean -xfdi
 4. git tag -a vX.X.X -m "Release vX.X.X"
-5. python setup.py sdist
-6. python setup.py bdist_wheel
-7. twine check dist/*
-8. twine upload dist/*
-9. git push upstream --tags
+5. python -m pip install --upgrade pip
+6. pip install --upgrade --upgrade-strategy eager build setuptools twine wheel
+7. python -bb -X dev -W error -m build
+8. twine check --strict dist/*
+9. twine upload dist/*
+10. git push upstream --tags
+11. Create release on Github