Add required PHP extensions to composer.json

Signed-off-by: Matthias Gutjahr <mattsches@gmail.com>

composer.json

@@ -6,6 +6,13 @@
     "type": "project",
     "require": {
         "php": "^7.1.3",
+        "ext-bcmath": "*",
+        "ext-ctype": "*",
+        "ext-curl": "*",
+        "ext-json": "*",
+        "ext-mbstring": "*",
+        "ext-openssl": "*",
+        "ext-redis": "*",
         "beyondcode/laravel-self-diagnosis": "^1.0.2",
         "bitverse/identicon": "^1.1",
         "doctrine/dbal": "^2.7",