feat: adding opensearch datasource to appsync

[ts-mini]

The Problem

Elasticsearch is deprecated in the datasource AWS API as AWS is moving towards their fork, OpenSearch. I realized upon attempting to apply this that opensearch is not currently supported by the provider, but it IS enabled in the aws-go-sdk as the exact same structure

The Solution

I thought it prudent to support the new method. Since as far as i can tell the two apis are largely the same...this is a lot of copy pasting w/ some name replacing

References

App Sync API Reference

As of September 2021, Amazon Elasticsearch service is Amazon OpenSearch Service. This configuration is deprecated. For new data sources, use [CreateDataSource:openSearchServiceConfig]

Notes

• first time contributing to the repo, added tests, ran them (i think all of them?)
• added changelog

Closes #29579.

[github-actions]

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[ewbankkit]

LGTM 🚀.

% make testacc TESTARGS='-run=TestAccAppSync_serial/^DataSource$$\|TestAccAppSyncDataSource_OpenSearchService_region\|TestAccAppSyncDataSource_Type_openSearchService' PKG=appsync ACCTEST_PARALLELISM=2
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/appsync/... -v -count 1 -parallel 2  -run=TestAccAppSync_serial/^DataSource$\|TestAccAppSyncDataSource_OpenSearchService_region\|TestAccAppSyncDataSource_Type_openSearchService -timeout 180m
=== RUN   TestAccAppSync_serial
=== PAUSE TestAccAppSync_serial
=== RUN   TestAccAppSyncDataSource_OpenSearchService_region
=== PAUSE TestAccAppSyncDataSource_OpenSearchService_region
=== RUN   TestAccAppSyncDataSource_Type_openSearchService
=== PAUSE TestAccAppSyncDataSource_Type_openSearchService
=== CONT  TestAccAppSync_serial
=== CONT  TestAccAppSyncDataSource_Type_openSearchService
=== RUN   TestAccAppSync_serial/DataSource
=== RUN   TestAccAppSync_serial/DataSource/basic
=== RUN   TestAccAppSync_serial/DataSource/Type_rdbms_options
=== RUN   TestAccAppSync_serial/DataSource/Type_eventBridge
=== RUN   TestAccAppSync_serial/DataSource/HTTP_endpoint
=== RUN   TestAccAppSync_serial/DataSource/type
=== RUN   TestAccAppSync_serial/DataSource/Type_http
=== RUN   TestAccAppSync_serial/DataSource/Type_none
=== RUN   TestAccAppSync_serial/DataSource/description
=== RUN   TestAccAppSync_serial/DataSource/DynamoDB_region
=== RUN   TestAccAppSync_serial/DataSource/Type_lambda
=== RUN   TestAccAppSync_serial/DataSource/DynamoDB_useCallerCredentials
=== RUN   TestAccAppSync_serial/DataSource/Type_dynamoDB
=== RUN   TestAccAppSync_serial/DataSource/Type_http_auth
=== RUN   TestAccAppSync_serial/DataSource/Type_rdbms
--- PASS: TestAccAppSync_serial (894.93s)
    --- PASS: TestAccAppSync_serial/DataSource (894.93s)
        --- PASS: TestAccAppSync_serial/DataSource/basic (18.62s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_rdbms_options (284.51s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_eventBridge (17.10s)
        --- PASS: TestAccAppSync_serial/DataSource/HTTP_endpoint (32.18s)
        --- PASS: TestAccAppSync_serial/DataSource/type (25.06s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_http (17.41s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_none (16.03s)
        --- PASS: TestAccAppSync_serial/DataSource/description (29.52s)
        --- PASS: TestAccAppSync_serial/DataSource/DynamoDB_region (40.02s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_lambda (34.30s)
        --- PASS: TestAccAppSync_serial/DataSource/DynamoDB_useCallerCredentials (42.24s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_dynamoDB (35.38s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_http_auth (18.70s)
        --- PASS: TestAccAppSync_serial/DataSource/Type_rdbms (283.85s)
=== CONT  TestAccAppSyncDataSource_OpenSearchService_region
--- PASS: TestAccAppSyncDataSource_Type_openSearchService (1503.13s)
--- PASS: TestAccAppSyncDataSource_OpenSearchService_region (1962.34s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/appsync	2862.578s

[ewbankkit]

@ts-mini Thanks for the contribution 🎉 👏.

[github-actions]

This functionality has been released in v4.64.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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