updates GPL to 3.0

composer.json

@@ -2,7 +2,7 @@
 	"name": "understrap/understrap",
 	"description": "Combines Automattic's Underscores Starter Theme and Bootstrap",
 	"type": "wordpress-theme",
-	"license": "GPL-2.0-only",
+	"license": "GPL-3.0",
 	"minimum-stability": "stable",
 	"keywords": [
 		"wordpress",

package-lock.json

@@ -7,7 +7,7 @@
     "": {
       "name": "understrap",
       "version": "1.1.0",
-      "license": "GPL-2.0",
+      "license": "GPL-3.0",
       "devDependencies": {
         "@babel/core": "^7.19.3",
         "@babel/preset-env": "^7.19.3",

package.json

@@ -46,7 +46,7 @@
     "underscores"
   ],
   "author": "The UnderStrap Authors (https://github.com/understrap/understrap/graphs/contributors)",
-  "license": "GPL-2.0",
+  "license": "GPL-3.0",
   "bugs": {
     "url": "https://github.com/understrap/understrap/issues"
   },