PHP 8 runtimes

[mnapoli]

This pull request adds PHP 8.0 runtimes.

These 8.0 runtimes are obviously experimental, use at your own risk. They are based on PHP 8.0.0-alpha1.

They do not include the redis or mongodb extension. The dev layer do not include Blackfire (doesn't support PHP 8.0 yet), but it does include XDebug 3.0-dev (master), which I haven't tested ;)

If you are interested in the details, nothing in particular changed in the build process compared to PHP 7.4.

---

I have built the layers for testing. I'll create the final layers after merging this PR.

If you want to give it a try in the meantime:

• arn:aws:lambda:us-east-1:416566615250:layer:php-80:1
• arn:aws:lambda:us-east-1:416566615250:layer:php-80-fpm:1

You can replace us-east-1 with any region, the layer version should always be 1.

Here is an example:

functions:
    web:
        handler: public/index.php
        layers:
-            - ${bref:layer.php-74-fpm}
+            - 'arn:aws:lambda:us-east-1:416566615250:layer:php-80-fpm:1'