Add deprecation notice for require_ssl field

[feng-zhe]

Related to issues/17443. Basically customers need to manually set compatible require_ssl and ssl_mode otherwise the request will fail. The require_ssl is legacy and its functionality can be fully replaced by ssl_mode.

To get rid of the burden, we have to deprecate the require_ssl in favor of the newer field ssl_mode. This PR adds the deprecation message for the field require_ssl.

Release Note Template for Downstream PRs (will be copied)

[github-actions]

Hello! I am a robot. Tests will require approval from a repository maintainer to run.

@NickElliot, a repository maintainer, has been assigned to review your changes. If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.

You can help make sure that review is quick by doing a self-review and by running impacted tests locally.

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 2 files changed, 3 insertions(+), 2 deletions(-))
google-beta provider: Diff ( 2 files changed, 3 insertions(+), 2 deletions(-))

[modular-magician]

Tests analytics

Total tests: 94
Passed tests: 74
Skipped tests: 14
Affected tests: 6

Click here to see the affected service packages

• sql

Action taken

Found 6 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

TestAccSqlDatabaseInstance_encryptionKey|TestAccSqlDatabaseInstance_encryptionKey_replicaInDifferentRegion|TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRange|TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRangeClone|TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRangeReplica|TestAccSqlDatabaseInstance_withPrivateNetwork_withoutAllocatedIpRange

Get to know how VCR tests work

[modular-magician]

$\textcolor{green}{\textsf{Tests passed during RECORDING mode:}}$
TestAccSqlDatabaseInstance_encryptionKey[Debug log]
TestAccSqlDatabaseInstance_encryptionKey_replicaInDifferentRegion[Debug log]
TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRange[Debug log]
TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRangeClone[Debug log]
TestAccSqlDatabaseInstance_withPrivateNetwork_withAllocatedIpRangeReplica[Debug log]
TestAccSqlDatabaseInstance_withPrivateNetwork_withoutAllocatedIpRange[Debug log]

$\textcolor{green}{\textsf{No issues found for passed tests after REPLAYING rerun.}}$

---

$\textcolor{green}{\textsf{All tests passed!}}$
View the build log or the debug log for each test

[github-actions]

This PR has been waiting for review for 2 weekdays. Please take a look! Use the label disable-review-reminders to disable these notifications.

[feng-zhe]

Friendly ping. Thanks.