feat: always use latest apollo sandbox

[gitxiongpan]

I am not sure whether there are any securiy concerns regarding loading latest apollo sanbox by default. For me, it makes sense to auto load the latest version.

I have:

• Added tests covering the bug / feature (see testing)
• Updated any relevant documentation (see docs)

[coveralls]

coverage: 79.177% (+0.02%) from 79.16% when pulling d955b63 on gitxiongpan:feat/always-use-latest-apollo-sanbox into ee6add4 on 99designs:master.

[StevenACoffman]

See #2581 for the history of this Apollo Sandbox playground feature.

The url https://embeddable-sandbox.cdn.apollographql.com/ will allow you to list the contents of the S3 bucket. I made a dumb script to figure out the latest one from the S3 bucket and calculate the Subresource Integrity. This script is https://gist.github.com/StevenACoffman/2f15cd2e64f107d1a9a5f10f9748e1b0 and when I run it:

CDN_FILE=https://embeddable-sandbox.cdn.apollographql.com/7212121cad97028b007e974956dc951ce89d683c/embeddable-sandbox.umd.production.min.js
curl -s $CDN_FILE | openssl dgst -sha256 -binary | openssl base64 -A; echo

ldbSJ7EovavF815TfCN50qKB9AMvzskb9xiG71bmg2I=

So instead of setting it to "_latest" and having to forego the subresource integrity check, let's just update both to that and now we can try to remember to periodically run this dumb script and update it. Ok?

[chadxzs]

perhaps something that could help is a GitHub Action to run the script and issue a PR on a cronjob schedule. I've not personally done this but a quick search shows GitHub has a 1st-class action for it.

[StevenACoffman]

Thanks for this PR! Looking forward to your next PR.