Update license identifier to match SPDX v3.0 (#7)

* Update composer.json
* Update extension.json

[skip ci]

Author: kghbln

composer.json

@@ -8,7 +8,7 @@
 		"parser function"
 	],
 	"homepage": "https://github.com/SemanticMediaWiki/Mermaid",
-	"license": "GPL-2.0+",
+	"license": "GPL-2.0-or-later",
 	"authors": [
 		{
 			"name": "mwjames",

extension.json

@@ -2,11 +2,11 @@
 	"name": "Mermaid",
 	"version": "1.0.0-alpha",
 	"author": [
-        "James Hong Kong"
+        	"James Hong Kong"
 	],
 	"url": "https://github.com/SemanticMediaWiki/Mermaid/",
 	"descriptionmsg": "mermaid-desc",
-	"license-name": "GPL-2.0+",
+	"license-name": "GPL-2.0-or-later",
 	"type": "parserhook",
 	"requires": {
 		"MediaWiki": ">= 1.27"
@@ -22,4 +22,4 @@
 	],
 	"load_composer_autoloader":true,
 	"manifest_version": 1
-}
+}