fix: add Bill Wallace to the contributors list

Bill Wallace maintains this fork: the byte-aligned-end-of-scan fix in
03bb80c, and the work that publishes the fork as
@cornerstonejs/jpeg-lossless-decoder-js.

The entry is the name alone, which matches the two entries beside it. npm also
accepts "Name <email> (url)", and an entry in a published package is public,
so the email stays out unless its owner asks for it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: wayfarer3130

package.json

@@ -53,7 +53,8 @@
   ],
   "author": "Michael Martinez",
   "contributors": [
-    "Helmut Dersch"
+    "Helmut Dersch",
+    "Bill Wallace"
   ],
   "license": "MIT",
   "bugs": {