Add confirmation step before the manual release

[csala]

In the Orion project we have introduced a confirmation step before pushing the new release to PyPI in the manual workflow to prevent releases from being made accidentally if PyPI credentials are configured in the user's .pypirc.

https://github.com/signals-dev/Orion/blob/584d7dc5dc247cfb615768b0cd473b9f664c1e3b/Makefile#L152

Now the release prompt looks like this:

$ make release
... merge to stable, bumpversion and dist happens here ...
WARNING: This will irreversibly upload a new version to PyPI!
Please type 'confirm' to proceed: confirm    <- confirm is typed by the user
... The new version files are uploaded to PyPI, also asking for username and password if .pypirc is not configured ...

May we add this to the cookiecutter template?

[csala]

@micahjsmith ?

[micahjsmith]

fine by me