fix: always add the cache policy (#528)

* Always add the cache policy

* fixed a typo in the cache docs

Author: kayman-mk

Diff for: README.md

@@ -166,7 +166,7 @@ A few option are provided to access the runner instance:
 
 ### GitLab runner cache
 
-By default the module creates a a cache for the runner in S3. Old objects are automatically removed via a configurable life cycle policy on the bucket.
+By default the module creates a cache for the runner in S3. Old objects are automatically removed via a configurable life cycle policy on the bucket.
 
 Creation of the bucket can be disabled and managed outside this module. A good use case is for sharing the cache across multiple runners. For this purpose the cache is implemented as a sub module. For more details see the [cache module](https://github.com/npalm/terraform-aws-gitlab-runner/tree/develop/cache). An example implementation of this use case can be found in the [runner-public](https://github.com/npalm/terraform-aws-gitlab-runner/tree/__GIT_REF__/examples/runner-public) example.
 

Diff for: main.tf

@@ -399,7 +399,6 @@ resource "aws_iam_role_policy_attachment" "user_defined_policies" {
 ### Policy for the docker machine instance to access cache
 ################################################################################
 resource "aws_iam_role_policy_attachment" "docker_machine_cache_instance" {
-  count      = var.cache_bucket["create"] || lookup(var.cache_bucket, "policy", "") != "" ? 1 : 0
   role       = aws_iam_role.instance.name
   policy_arn = local.bucket_policy
 }