Update layers

Update layer versions for new runtimes

Merge pull request brefphp#580 from tristanbes/patch-1

Update case-studies.md

Update layer versions

Merge pull request brefphp#551 from brefphp/improve-deploy-docs

Improve documentation for on-boarding new users

Update layer versions

Update Bref layers

Merge pull request brefphp#519 from Nyholm/tag

Tag docker images when tag on Github

Publish runtimes for PHP 7.4

Upgrade layer versions