Remove public keyword from Downloader and Installer interface methods

src/Composer/Downloader/DownloaderInterface.php

@@ -31,5 +31,5 @@ interface DownloaderInterface
      *
      * @throws \UnexpectedValueException
      */
-    public function download(PackageInterface $package, $path, $url, $checksum = null);
+    function download(PackageInterface $package, $path, $url, $checksum = null);
 }

src/Composer/Installer/InstallerInterface.php

@@ -29,5 +29,5 @@ interface InstallerInterface
      * @param DownloaderInterface $downloader
      * @param string              $type
      */
-    public function install(PackageInterface $package, DownloaderInterface $downloader, $type);
+    function install(PackageInterface $package, DownloaderInterface $downloader, $type);
 }