Update phpcs, phpcpd, and phpunit.

- Update phpcs to ^3.0
- Update phpcpd to ^6.0
- Update phpunit to ^9.0
- Set php to ^7.3 or ^7.4

composer.json

@@ -29,17 +29,18 @@
     "drupal/token" : "^1.3",
     "drupal/flysystem" : "^1.0",
     "islandora/crayfish-commons": "dev-dev",
-    "drupal/file_replace": "^1.1"
+    "drupal/file_replace": "^1.1",
+    "php": "^7.3 || ^7.4"
 
   },
   "require-dev": {
-    "phpunit/phpunit": "^6",
+    "phpunit/phpunit": "^9",
-    "squizlabs/php_codesniffer": "2.7.1",
+    "squizlabs/php_codesniffer": "^3.0",
     "drupal/coder": "*",
-    "sebastian/phpcpd": "*"
+    "sebastian/phpcpd": "^6"
   },
   "suggest": {
-    "drupal/transliterate_filenames": "Sanitizes filenames when they are uploaded so they don't break your repository." 
+    "drupal/transliterate_filenames": "Sanitizes filenames when they are uploaded so they don't break your repository."
   },
   "license": "GPL-2.0+",
   "authors": [