Upgrade CommonMark and use the bundled table extension (#31411)

league/commonmark 1.3 now includes the official extensions directly in
the main projects.  The separate extension packages (like
`league/commonmark-ext-table`) are being deprecated in the very near
future.

For more information, please see:
https://www.colinodell.com/blog/202002/league-commonmark-130-adds-full-gfm-support

composer.json

@@ -22,8 +22,7 @@
         "doctrine/inflector": "^1.1",
         "dragonmantank/cron-expression": "^2.0",
         "egulias/email-validator": "^2.1.10",
-        "league/commonmark": "^1.1",
-        "league/commonmark-ext-table": "^2.1",
+        "league/commonmark": "^1.3",
         "league/flysystem": "^1.0.8",
         "monolog/monolog": "^1.12|^2.0",
         "nesbot/carbon": "^2.0",

src/Illuminate/Mail/Markdown.php

@@ -7,7 +7,7 @@
 use Illuminate\Support\Str;
 use League\CommonMark\CommonMarkConverter;
 use League\CommonMark\Environment;
-use League\CommonMark\Ext\Table\TableExtension;
+use League\CommonMark\Extension\Table\TableExtension;
 use TijsVerkoyen\CssToInlineStyles\CssToInlineStyles;
 
 class Markdown

src/Illuminate/Mail/composer.json

@@ -19,8 +19,7 @@
         "illuminate/container": "^6.0",
         "illuminate/contracts": "^6.0",
         "illuminate/support": "^6.0",
-        "league/commonmark": "^1.1",
-        "league/commonmark-ext-table": "^2.1",
+        "league/commonmark": "^1.3",
         "psr/log": "^1.0",
         "swiftmailer/swiftmailer": "^6.0",
         "tijsverkoyen/css-to-inline-styles": "^2.2.1"