Avoid validating package name if it has a newline at the end

src/Composer/Command/InitCommand.php

@@ -214,7 +214,7 @@ EOT
             }
             $name = strtolower($name);
         } else {
-            if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}', $name)) {
+            if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}D', $name)) {
                 throw new \InvalidArgumentException(
                     'The package name '.$name.' is invalid, it should be lowercase and have a vendor name, a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+'
                 );
@@ -228,7 +228,7 @@ EOT
                     return $name;
                 }
 
-                if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}', $value)) {
+                if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}D', $value)) {
                     throw new \InvalidArgumentException(
                         'The package name '.$value.' is invalid, it should be lowercase and have a vendor name, a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+'
                     );