update JSON string encodings in author directory

The following characters are no longer encoded
and are represented as themselves:

- & is no longer encoded
- / is no longer encoded
- < is no longer encoded
- > is no longer encoded
- [\x80-\xff] is no longer encoded

The author ID JSON files under `/author` have
been updated accordingly.

author/Yusuke_Endoh.json

@@ -11,7 +11,7 @@
     "alt_url" : null,
     "deprecated_twitter_handle" : null,
     "mastodon" : "@mame@ruby.social",
-    "mastodon_url" : "http:\/\/ruby.social\/@mame",
+    "mastodon_url" : "https://ruby.social/@mame",
     "github" : null,
     "affiliation" : null,
     "winning_entry_set" : [