chore: update license

Author: azu

README.md

@@ -123,7 +123,7 @@ module.exports.get = function get(ext = ".*") {};
 - [progit](https://github.com/progit/progit)
   - License: <https://git-scm.com/book/en/v2>
 - [what-is-maven](https://github.com/KengoTODA/what-is-maven)
-  - License: <https://github.com/KengoTODA/what-is-maven/blob/master/preface.md#%E3%83%A9%E3%82%A4%E3%82%BB%E3%83%B3%E3%82%B9>
+  - License: <https://github.com/KengoTODA/what-is-maven/blob/main/preface/README.md>
 - [Hatena-Textbook](https://github.com/hatena/Hatena-Textbook)
   - License: <https://github.com/hatena/Hatena-Textbook#%E3%83%A9%E3%82%A4%E3%82%BB%E3%83%B3%E3%82%B9>
 - [build-web-application-with-golang](https://github.com/astaxie/build-web-application-with-golang)

index.js

@@ -35,7 +35,7 @@ const References = {
     "what-is-maven": {
         name: "what-is-maven",
         url: "https://github.com/KengoTODA/what-is-maven",
-        license: "https://github.com/KengoTODA/what-is-maven/blob/master/preface.md#%E3%83%A9%E3%82%A4%E3%82%BB%E3%83%B3%E3%82%B9"
+        license: "https://github.com/KengoTODA/what-is-maven/blob/main/preface/README.md"
     },
     "Hatena-Textbook": {
         name: "Hatena-Textbook",