Update to ACK runtime v0.56.0, code-generator v0.56.0 (#61)

### 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 `v1.3.2` to `v1.4.0`

Once this PR is merged, release `v1.4.0` will be automatically created for `apigateway-controller`

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

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

```
building ack-generate ... ok.
==== building apigateway-controller ====
Copying common custom resource definitions into apigateway
Building Kubernetes API objects for apigateway
Generating deepcopy code for apigateway
Generating custom resource definitions for apigateway
Building service controller for apigateway
Running GO mod tidy
Generating RBAC manifests for apigateway
Running gofmt against generated code for apigateway
Updating additional GitHub repository maintenance files
==== building apigateway-controller release artifacts ====
Building release artifacts for apigateway-v1.4.0
Generating common custom resource definitions
Generating custom resource definitions for apigateway
Generating RBAC manifests for apigateway
```

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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