Resolve #3147278 "Drupal 9 compatibility support esc 8.0.x branch"

Closes #3147278

composer.json

@@ -4,6 +4,12 @@
     "type": "drupal-module",
     "homepage": "https://drupal.org/project/elasticsearch_aws_connector",
     "license": "GPL-2.0+",
+    "repositories": [
+      {
+        "type": "composer",
+        "url": "https://packages.drupal.org/8"
+      }
+    ],
     "authors": [
         {
             "name": "Jochen Verdeyen (jover)",
@@ -15,9 +21,11 @@
         "issues": "https://www.drupal.org/project/issues/elasticsearch_aws_connector",
         "source": "http://cgit.drupalcode.org/elasticsearch_aws_connector"
     },
+    "minimum-stability": "dev",
+    "prefer-stable": true,
     "require": {
-        "drupal/core": "^8",
-        "drupal/elasticsearch_connector": "5.x-dev",
-        "jsq/amazon-es-php": "^0.2.0"
+        "drupal/core": "^8 || ^9",
+        "drupal/elasticsearch_connector": "^8.0.x-dev",
+        "jsq/amazon-es-php": "^0.3.0"
     }
-}
\ No newline at end of file
+}