Update instructions to use twine

pypi_upload.md

@@ -2,25 +2,27 @@
 
 Notes to remind @zimeon...
 
-iiif-prezi is at <https://pypi.python.org/pypi/iiif-prezi>
+  * master copy of code is https://github.com/iiif-prezi/iiif-prezi
+  * on PyPi iiif-prezi is at <https://pypi.org/project/iiif-prezi/>
 
 Putting up a new version
 ------------------------
 
   0. Bump version number working branch in `iiif_prezi/_version.py`
   1. Check all tests good (`python setup.py test`)
-  2. Check code is up-to-date with github version
+  2. Check code is up-to-date with master github version
   3. Check out master and merge in working branch
   4. Check all tests good (`python setup.py test`)
-  5. Make sure master README has correct travis-ci and coveralls icon links for master branch (`?branch=master`)
-  6. Check branches are as expected (`git branch -a`)
-  7. Check local build and version reported OK (`python setup.py build; python setup.py install`)
-  8. Upload new version to pypi:
+  5. Check branches are as expected (`git branch -a`)
+  6. Check local build and version reported OK (`python setup.py build; python setup.py install`)
+  7. Upload new version to pypi using Python 3.x:
 
     ```
-    python setup.py sdist upload
+    pip install --upgrade setuptools wheel twine
+    python setup.py sdist bdist_wheel
+    ls dist
+    twine upload dist/*
     ```
 
-  9. Check on PyPI at <https://pypi.python.org/pypi/iiif-prezi>
-
+  8. Check on PyPI at <https://pypi.org/project/iiif-prezi/>