Replace deprecated ${var} string interpolation with {$var} interpolation

src/Adapter/FastCGI.php

@@ -79,7 +79,7 @@ public function __construct($host = null, $chroot = null)
             if (preg_match($IPv6, $host) === 1) {
                 // IPv6 addresses need to be surrounded by brackets
                 // see: https://www.php.net/manual/en/function.stream-socket-client.php#refsect1-function.stream-socket-client-notes
-                $host = "[${host}]";
+                $host = "[{$host}]";
             }
 
             $this->connection = new NetworkSocket(

src/Adapter/Http/FileGetContents.php

@@ -24,7 +24,7 @@ public function fetch($filename)
                 'errors' => [
                     [
                         'no' => 0,
-                        'str' => "file_get_contents() call failed with url: ${url}",
+                        'str' => "file_get_contents() call failed with url: {$url}",
                     ],
                 ],
             ]);

src/Command/AbstractOpcacheCommand.php

@@ -24,7 +24,7 @@ protected function ensureSuccessfulOpcacheCall($info)
 
         if ($info['restart_pending'] ?? false) {
             $cacheStatus = $info['cache_full'] ? 'Also, you cache is full.' : '';
-            throw new \RuntimeException("OPCache is restart, as such files can't be invalidated. Try again later. ${cacheStatus}");
+            throw new \RuntimeException("OPCache is restart, as such files can't be invalidated. Try again later. {$cacheStatus}");
         }
 
         $file_cache_only = $info['file_cache_only'] ?? false;

src/Command/OpcacheResetFileCacheCommand.php

@@ -44,7 +44,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 
         if (!$input->getOption('force')) {
             $question = new ConfirmationQuestion(
-                "Are you sure you want to delete the contents of <comment>${fileCache}</comment>? [no] ",
+                "Are you sure you want to delete the contents of <comment>{$fileCache}</comment>? [no] ",
                 false,
                 '/^y/i'
             );