Composer: coding standard is a dev requirement

... not a runtime dependency.

Author: jrfnl

composer.json

@@ -4,8 +4,7 @@
     "type": "library",
     "require": {
         "phpunit/phpunit": "^9.0",
-        "php": "^7.3|^7.4|^8.0",
-        "dms/coding-standard": "^8"
+        "php": "^7.3|^7.4|^8.0"
     },
     "license": "MIT",
     "authors": [
@@ -15,7 +14,8 @@
         }
     ],
     "require-dev": {
-        "squizlabs/php_codesniffer": "^3.4"
+        "squizlabs/php_codesniffer": "^3.4",
+        "dms/coding-standard": "^8"
     },
     "autoload": {
         "psr-4": {