feat: 👍 add Japanese language

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "hugo-congo-theme",
-  "version": "2.2.2",
+  "version": "2.3.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "hugo-congo-theme",
-      "version": "2.2.2",
+      "version": "2.3.0",
       "hasInstallScript": true,
       "license": "MIT",
       "devDependencies": {
@@ -20,6 +20,9 @@
         "rimraf": "^3.0.2",
         "tailwindcss": "^3.1.4",
         "vendor-copy": "^3.0.1"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/jpanther"
       }
     },
     "node_modules/@braintree/sanitize-url": {