Add new "wp-config-docker.php" that uses "getenv" for configuration

This new method of configuration allows us to stop modifying the user-supplied `wp-config.php` file on every container startup, and instead just let PHP itself read the values directly from the source.

With this change, the "beta" tags are force-reenabled at the same version as the latest releases to allow users to test this before the next release of WordPress (where it is intended that this change will go live for all image variants).

.gitattributes

@@ -1,3 +1,4 @@
 /*/**/Dockerfile            linguist-generated
 /*/**/docker-entrypoint.sh  linguist-generated
+/*/**/wp-config-docker.php  linguist-generated
 /Dockerfile.template        linguist-language=Dockerfile

Dockerfile.template

@@ -229,6 +229,9 @@ RUN set -ex; \
 
 VOLUME /var/www/html
 
+{{ if env.version == "beta" then ( -}}
+COPY --chown=www-data:www-data wp-config-docker.php /usr/src/wordpress/
+{{ ) else "" end -}}
 COPY docker-entrypoint.sh /usr/local/bin/
 
 ENTRYPOINT ["docker-entrypoint.sh"]

apply-templates.sh

@@ -52,6 +52,9 @@ for version; do
 
 			if [ "$version" = 'cli' ]; then
 				cp -a cli-entrypoint.sh "$dir/docker-entrypoint.sh"
+			elif [ "$version" = 'beta' ]; then
+				cp -a docker-entrypoint-ng.sh "$dir/docker-entrypoint.sh"
+				cp -a wp-config-docker.php "$dir/"
 			else
 				cp -a docker-entrypoint.sh "$dir/"
 			fi