Document PHP 7.1 support

Fixes #2302

README.md

@@ -60,7 +60,7 @@ With PHPWord, you can create OOXML, ODF, or RTF documents dynamically using your
 
 PHPWord requires the following:
 
-- PHP 7.4+
+- PHP 7.1+
 - [XML Parser extension](http://www.php.net/manual/en/xml.installation.php)
 - [Laminas Escaper component](https://docs.laminas.dev/laminas-escaper/intro/)
 - [Zip extension](http://php.net/manual/en/book.zip.php) (optional, used to write OOXML and ODF)

docs/installing.rst

@@ -9,7 +9,7 @@ Requirements
 Mandatory:
 
 - composer
-- PHP 7.4+
+- PHP 7.1+
 - `XML Parser <http://www.php.net/manual/en/xml.installation.php>`__ extension
 
 Optional:

samples/index.php

@@ -4,7 +4,7 @@ include_once 'Sample_Header.php';
 use PhpOffice\PhpWord\Settings;
 
 $requirements = [
-    'php' => ['PHP 7.4', version_compare(PHP_VERSION, '7.4', '>=')],
+    'php' => ['PHP 7.1', version_compare(PHP_VERSION, '7.1', '>=')],
     'xml' => ['PHP extension XML', extension_loaded('xml')],
     'temp' => ['Temp folder "<code>' . Settings::getTempDir() . '</code>" is writable', is_writable(Settings::getTempDir())],
     'zip' => ['PHP extension ZipArchive (optional)', extension_loaded('zip')],