chore: restore bin to composer for running tests on windows

Using the bin property in composer.json allows Composer to convert the
provided scripts to .bat files for execution on Windows, so when running
`composer lint`, it will properly execute the script in Windows
environments.

Author: ramsey

composer.json

@@ -39,10 +39,14 @@
             "configFile": "conventional-commits.json"
         }
     },
+    "bin": [
+        "bin/xmllint",
+        "bin/xmllint-fix"
+    ],
     "scripts": {
         "post-autoload-dump": "captainhook install --ansi -f -s",
-        "lint": "./bin/xmllint",
-        "lint:fix": "./bin/xmllint-fix",
+        "lint": "xmllint",
+        "lint:fix": "xmllint-fix",
         "test": "@lint"
     },
     "scripts-descriptions": {