Bump minimum version to run Friendica to PHP 7.4

- Update version filter of mobiledetect/mobiledetectlib and psr/container to PHP 7.4 versions
- Remove PHP 7.3 PHPUnit instance
- Remove PHP 7.2 specific PDO exception in tests

composer.json

@@ -13,7 +13,7 @@
 		"issues": "https://github.com/friendica/friendica/issues"
 	},
 	"require": {
-		"php": ">=7.3",
+		"php": ">=7.4",
 		"ext-ctype": "*",
 		"ext-curl": "*",
 		"ext-dom": "*",
@@ -44,7 +44,7 @@
 		"mattwright/urlresolver": "^2.0",
 		"michelf/php-markdown": "^1.7",
 		"minishlink/web-push": "^6.0",
-		"mobiledetect/mobiledetectlib": "^2.8",
+		"mobiledetect/mobiledetectlib": "^3.74",
 		"nikic/fast-route": "^1.3",
 		"paragonie/hidden-string": "^1.0",
 		"patrickschur/language-detection": "^5.0.0",
@@ -53,7 +53,7 @@
 		"pragmarx/google2fa": "^5.0",
 		"pragmarx/recovery": "^0.2",
 		"psr/clock": "^1.0",
-		"psr/container": "^1.0",
+		"psr/container": "^2.0",
 		"psr/log": "^1.1",
 		"seld/cli-prompt": "^1.0",
 		"smarty/smarty": "^4",
@@ -102,7 +102,7 @@
 	},
 	"config": {
 		"platform": {
-			"php": "7.3"
+			"php": "7.4"
 		},
 		"autoloader-suffix": "Friendica",
 		"optimize-autoloader": true,