feat(er): supports new resource to update the attachment infos

[Lance52259]

What this PR does / why we need it:
Add new resource to do attachment update operation.

Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #xxx

Special notes for your reviewer:

Release note:

1. Supports new resource to update the attachment infos.

PR Checklist

• Tests added/passed.

./scripts/coverage.sh -o er -f TestAccAttachmentUpdate_basic
Prepare to calculate the coverage the following command:
TF_ACC=1 go test "./huaweicloud/services/acceptance/er" -v -coverprofile="./huaweicloud/services/acceptance/er/er_coverage.cov" -coverpkg="./huaweicloud/services/er" -run TestAccAttachmentUpdate_basic -timeout 360m -parallel 10
=== RUN   TestAccAttachmentUpdate_basic
=== PAUSE TestAccAttachmentUpdate_basic
=== CONT  TestAccAttachmentUpdate_basic
--- PASS: TestAccAttachmentUpdate_basic (123.58s)
PASS
coverage: 15.5% of statements in ./huaweicloud/services/er
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/er        123.698s        coverage: 15.5% of statements in ./huaweicloud/services/er

• Documentation updated.

• Schema updated.

• CheckDeleted.

  • a. During query operation (Read Context)
    aa. Resource not found
    

  • b. During delete/disassociate/unbind operation (Delete Context)
    ba. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

[github-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This PR has been approved by: @Lance52259