Update documentation and composer file with correct git repo Homepage

The correct place is at the EGRA github org, reference original in
the description.

Update the require part for the composer json file with this new information

composer.json

@@ -1,11 +1,11 @@
 {
     "name": "egrajp/smarty-extended",
-    "description": "Smarty, extended with gettext, checkbox/radio labels and index numbers",
+    "description": "Smarty, extended with gettext, checkbox/radio labels and index numbers. Based on the smarty project: https://github.com/smarty-php/smarty/",
     "type": "library",
     "keywords": [
         "templating"
     ],
-    "homepage": "https://github.com/smarty-php/smarty/",
+    "homepage": "https://github.com/TBWA-EGPlus-Japan/Composer.smarty-extended",
     "license": "LGPL-3.0",
     "autoload": {
         "files": [
@@ -28,7 +28,11 @@
             "url": "https://git.egplusww.jp/api/packages/Composer/composer"
         }
     },
+    "require": {
+        "php": "^7.4 || ^8.0",
+        "ext-mbstring": "*"
+    },
     "require-dev": {
-        "egrajp/corelibs-composer-all": "^9.13"
+        "egrajp/corelibs-composer-all": "^9"
     }
 }