🐛 Create a aws.Config with region to be able to work different AWS partition (like gov cloud or china AWS partition)

[calvix]

What type of PR is this?
/kind bug

What this PR does / why we need it:
When creating aws.Config without specifying a region the AWS SDK will by default call AWS commercial partition (known as just aws) .

If you wanna use a different AWS partition (https://docs.aws.amazon.com/whitepapers/latest/aws-fault-isolation-boundaries/partitions.html and https://docs.aws.amazon.com/IAM/latest/UserGuide/reference-arns.html ) like for example aws-cn and provide static access keys to the user that is in aws-cn partition then the controller fails with error since AWS SDK tries to validate the access keys in aws commercial partition.

 > controller="awscluster" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="AWSCluster" AWSCluster="org-giantswarm/galaxy" namespace="org-giantswarm" name="galaxy" reconcileID="e4da8234-95e0-476b-868f-d7c4aeda498c"
E0306 10:02:50.109642       1 controller.go:324] "Reconciler error" err=<
   error getting infra provider cluster or control plane object: failed to create aws session: Failed to retrieve identity credentials: InvalidClientTokenId: The security token included in the request is invalid.
   	status code: 403, request id: 391bd0ff-52b9-412d-8d03-82aa8d720bd5
> controller="awsmachine" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="AWSMachine" AWSMachine="org-giantswarm/galaxy-control-plane-12c432c9-qrtwx" namespace="org-giantswarm" name="galaxy-control-plane-12c432c9-qrtwx" reconcileID="74834d11-ff72-464a-b63c-df993020ad38"
E0306 10:02:50.187222       1 controller.go:324] "Reconciler error" err=<
   error getting infra provider cluster or control plane object: failed to create aws session: Failed to retrieve identity credentials: InvalidClientTokenId: The security token included in the request is invalid.
   	status code: 403, request id: 63ba0c98-c34e-42c4-a276-4fbccc855908
> controller="awsmachine" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="AWSMachine" AWSMachine="org-giantswarm/galaxy-control-plane-12c432c9-hpgm5" namespace="org-giantswarm" name="galaxy-control-plane-12c432c9-hpgm5" reconcileID="9246fa92-2b5f-40ab-8e82-5ca5cc464133"
E0306 10:02:50.202148       1 controller.go:324] "Reconciler error" err=<
   error getting infra provider cluster or control plane object: failed to create aws session: Failed to retrieve identity credentials: InvalidClientTokenId: The security token included in the request is invalid.
   	status code: 403, request id: 2ff4274b-1075-454f-ad2a-9002de92f501
> controller="awsmachine" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="AWSMachine" AWSMachine="org-giantswarm/galaxy-control-plane-12c432c9-bdtfw" namespace="org-giantswarm" name="galaxy-control-plane-12c432c9-bdtfw" reconcileID="80073767-a7ff-44b0-b866-7ef1d16c676d"
E0306 10:08:18.496207       1 controller.go:324] "Reconciler error" err=<
   failed to create scope: failed to create aws session: Failed to retrieve identity credentials: InvalidClientTokenId: The security token included in the request is invalid.
   	status code: 403, request id: b1c30992-fdce-48e9-a66b-f951a4fd223d
   sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/scope.NewClusterScope
   	/workspace/pkg/cloud/scope/cluster.go:76
   sigs.k8s.io/cluster-api-provider-aws/v2/controllers.(*AWSClusterReconciler).Reconcile
   	/workspace/controllers/awscluster_controller.go:173

When the aws.Config is created with the proper region then the AWS SDK will connect to the right aws partition and correctly check for the validity of the static access key. And this is exactly what this PR fixes

• squashed commits

Release note:

Create `aws.Config` with a region to be able to work with different AWS partitions

[k8s-ci-robot]

Hi @calvix. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[vincepri]

/lgtm

[vincepri]

/ok-to-test

[k8s-ci-robot]

@calvix: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-provider-aws-apidiff-main	a617ca1	link	false	/test pull-cluster-api-provider-aws-apidiff-main

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[calvix]

this line is the core change, the rest is just wiring the region value to be able to use it here

[vincepri]

/approve
/assign @nrb

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vincepri

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [vincepri]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[nrb]

/lgtm