fix(modules): add required_providers in modules (#224)

The required_providers is a specification required to ensure that a
module defines its dependencies.
This PR fixes the absence.

modules/aurora/versions.tf

@@ -0,0 +1,10 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 5.35.0"
+    }
+  }
+}

modules/eks-cluster/versions.tf

@@ -0,0 +1,10 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 5.35.0"
+    }
+  }
+}

modules/fixtures/backend.tf

@@ -1,14 +1,5 @@
 # this file is used to declare a backend used during the tests
 
 terraform {
-  required_version = ">= 1.0"
-
-  required_providers {
-    aws = {
-      source  = "hashicorp/aws"
-      version = ">= 5.35.0"
-    }
-  }
-
   backend "s3" {}
 }

modules/opensearch/versions.tf

@@ -0,0 +1,10 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 5.35.0"
+    }
+  }
+}