Update to ACK runtime v0.56.0, code-generator v0.56.0 (#59)

### Update to ACK runtime `v0.56.0`, code-generator `v0.56.0`

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* ACK code-generator `v0.56.0` [release notes](https://github.com/aws-controllers-k8s/code-generator/releases/tag/v0.56.0)
* ACK runtime `v0.56.0` [release notes](https://github.com/aws-controllers-k8s/runtime/releases/tag/v0.56.0)

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NOTE:
This PR increments the release version of service controller from `v1.1.2` to `v1.2.0`

Once this PR is merged, release `v1.2.0` will be automatically created for `organizations-controller`

**Please close this PR, if you do not want the new patch release for `organizations-controller`**

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#### stdout for `make build-controller`:

```
building ack-generate ... ok.
==== building organizations-controller ====
Copying common custom resource definitions into organizations
Building Kubernetes API objects for organizations
Generating deepcopy code for organizations
Generating custom resource definitions for organizations
Building service controller for organizations
Running GO mod tidy
Generating RBAC manifests for organizations
Running gofmt against generated code for organizations
Updating additional GitHub repository maintenance files
==== building organizations-controller release artifacts ====
Building release artifacts for organizations-v1.2.0
Generating common custom resource definitions
Generating custom resource definitions for organizations
Generating RBAC manifests for organizations
```

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: ack-bot

.github/workflows/postsubmit.yaml

@@ -0,0 +1,10 @@
+name: Hydrate Go Proxy
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  call-hydrate-go-proxy:
+    uses: aws-controllers-k8s/.github/.github/workflows/reusable-postsubmit.yaml@main