CI: Setting up ssh key to upload prod docs
When we pushed the tag for pandas 1.5.0rc0 our docs build failed because we didn't have the ssh copied when trying to upload the docs to the server. This PR fixes that. Also, the web will be updated, which I'm not sure if it has any effect, as we may not be using the tags, but probably a good idea anyway.
Marking this as 1.5 since I think that's next available opportunity that we will make a tag. cc @simonjayhawkins  I reverted the push of the website and the dev docs. I didn't realize that the `checkout` action should be fetching the repo at the tag version. This can  mean checking out for example 1.4.5, which will have an outdated version of the website and the dev docs.

So, fixing the push of the released docs in this PR, and I reverted the update of web and dev docs. Thanks @datapythonista 