[ticket/16649] Set PHP 7.3.0 as a minimum required version

Also rebase and fix composer.lock conflict

PHPBB3-16649

phpBB/composer.json

@@ -25,14 +25,16 @@
 		"phpbb/phpbb-core": "self.version"
 	},
 	"require": {
-		"php": "^7.2.5",
+		"php": "^7.3 || ^8.0",
 		"ext-json": "*",
 		"ext-mbstring": "*",
+		"ext-pdo": "*",
 		"bantu/ini-get-wrapper": "~1.0",
 		"chita/topological_sort": "^3.0",
 		"composer/composer": "^2.0",
 		"composer/installers": "^1.9",
 		"composer/package-versions-deprecated": "^1.11",
+		"doctrine/dbal": "^3.0",
 		"google/recaptcha": "~1.1",
 		"guzzlehttp/guzzle": "~6.3",
 		"lusitanian/oauth": "^0.8.1",
@@ -74,7 +76,7 @@
 	},
 	"config": {
 		"platform": {
-			"php": "7.2.5"
+			"php": "7.3.0"
 		}
 	}
 }