Build/Test Tools: Change 5.5 default values of LOCAL_PHP/LOCAL_DB_VERSION.

This changes the default values for `LOCAL_PHP` and `LOCAL_DB_VERSION` in the 5.5 branch from `latest` to `7.4-fpm` and `5.7`, respectively, to properly reflect the highest versions of PHP and MySQL that this branch will support.

See #61533.

git-svn-id: https://develop.svn.wordpress.org/branches/5.5@58668 602fd350-edb4-49c9-b593-d223f7449a82

Author: desrosj

.env

@@ -16,7 +16,7 @@ LOCAL_PORT=8889
 LOCAL_DIR=src
 
 # The PHP version to use. Valid options are 'latest', and '{version}-fpm'.
-LOCAL_PHP=latest
+LOCAL_PHP=7.4-fpm
 
 ##
 # The PHPUnit version to use when running tests.

docker-compose.yml

@@ -32,7 +32,7 @@ services:
   # The PHP container.
   ##
   php:
-    image: wordpressdevelop/php:${LOCAL_PHP-latest}
+    image: wordpressdevelop/php:${LOCAL_PHP-7.4-fpm}
 
     networks:
       - wpdevnet
@@ -62,7 +62,7 @@ services:
   # The MySQL container.
   ##
   mysql:
-    image: ${LOCAL_DB_TYPE-mysql}:${LOCAL_DB_VERSION-latest}
+    image: ${LOCAL_DB_TYPE-mysql}:${LOCAL_DB_VERSION-5.7}
     platform: linux/amd64
 
     networks:
@@ -121,7 +121,7 @@ services:
   # The PHPUnit container.
   ##
   phpunit:
-    image: wordpressdevelop/phpunit:${LOCAL_PHPUNIT-latest}
+    image: wordpressdevelop/phpunit:${LOCAL_PHPUNIT-7.4-fpm}
 
     networks:
       - wpdevnet