Add GitHub Actions for deploys to WordPress.org

[jeffpaul]

Description of the Change

• Deploys newly tagged releases on GitHub to WordPress.ORG SVN
• Deploys single commits to master that only affecting readme and asset files on GitHub to WordPress.ORG SVN

Benefits

• Automates deploys to WordPress.ORG SVN and eliminates future human error

Possible Drawbacks

• Requires GitHub Actions to be available and free to @WordPress org account
• Requires an SVN_USERNAME and SVN_PASSWORD secret be set within the Settings of this wp-lazy-loading GitHub repo
• Requires the above mentioned SVN username and password be a valid WordPress.ORG SVN account with access to the wp-lazyloading` WordPress.ORG SVN repo

Applicable Issues

Relates to #1

[jeffpaul]

Note that I didn't say this PR closes the related issue as there are additional steps needed, as noted in the Possible Drawbacks section, in order for these GitHub Actions to function properly.

[tillkruss]

Nice work 👍🏻

[felixarntz]

@jeffpaul This would be really neat. I'm just a bit wary about the SVN username and password - of course it's needed, but I'm not sure what we could do here. I personally at least rather wouldn't provide mine.

[jeffpaul]

@felixarntz the SVN username and password are encrypted GitHub secrets, so if your concern is someone else gaining access to your credentials that seems like a low probability. If your concern relates to the account being tied to you instead of some generic core/committer account, then maybe see if someone from Systems or Meta could have the .org @wordpressdotorg account's SVN credentials added as GitHub secrets (or some similar account)?

[peterwilsoncc]

@felixarntz

To avoid storing the credentials of a personal account, I recommend setting up a bot account for the purpose. I use peterwilsoncc-syncbot on wp.org, for example.

It will allow you to give the account minimum required permissions, I certainly recommend against storing the credentials of an account with core commit in the GH secrets.

To reenforce @jeffpaul's point, not even the account that added them can see the secrets once they're stored.

[peterwilsoncc]

Setting up same for peterwilsoncc/rapid-canoncial-urls I needed to include GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} for the commit to work in each of these config files. I'm not sure why but I think it may have something to do with re-checkout. 🤷🏻‍♂️