docs: fix Postgre DSN sample

[kenjis]

Description
See #8771

The following setting

'DSN' => 'Postgre://postgres:postgres@localhost:5432/test?charset=utf8&connect_timeout=5&sslmode=1',    

causes the error:

CodeIgniter\Database\Exceptions\DatabaseException: Unable to connect to the database.
Main connection [Postgre]: pg_connect(): Unable to connect to PostgreSQL server: invalid sslmode value: "1"

See "Table 33.1. SSL Mode Descriptions"
in https://www.postgresql.org/docs/12/libpq-ssl.html#LIBPQ-SSL-PROTECTION

Checklist:

• Securely signed commits
• [] Component(s) with PHPDoc blocks, only if necessary or adds value
• [] Unit testing, with >80% coverage
• User guide updated
• [] Conforms to style guide

[datamweb]

Is there any statistics to know what percentage of servers have ssl configuration set as default.

[kenjis]

I have confirmed the following works:
'DSN' => 'Postgre://postgres:postgres@localhost:5432/test?charset=utf8&connect_timeout=5&sslmode=disable',

[kenjis]

By Claude 3 Haiku:
Unfortunately, I do not have access to comprehensive statistics on the percentage of PostgreSQL servers that have SSL/TLS configuration set as the default. The usage of SSL/TLS in PostgreSQL deployments can vary widely depending on factors such as industry, organization size, security requirements, and geographic region.

However, here are a few insights that may be helpful:

1. PostgreSQL Documentation Recommendation: The official PostgreSQL documentation strongly recommends using SSL/TLS for all client-server communications, stating that "it is strongly recommended that all PostgreSQL installations use SSL connections by default."

2. Industry Trends and Compliance: Many industries, such as finance, healthcare, and government, have regulatory requirements that mandate the use of encryption for data in transit, including database connections. This has likely driven increased adoption of SSL/TLS in PostgreSQL deployments within these sectors.

3. Open-Source Community Practices: The PostgreSQL open-source community is generally security-conscious and tends to advocate for the use of SSL/TLS. Many PostgreSQL deployment guides and best practices recommend enabling SSL/TLS by default.

4. Cloud-based PostgreSQL Services: Cloud-based PostgreSQL services, such as Amazon RDS for PostgreSQL and Google Cloud SQL for PostgreSQL, often have SSL/TLS encryption enabled by default to meet security standards and provide a more secure out-of-the-box experience.

While precise statistics are not readily available, it is safe to assume that the adoption of SSL/TLS in PostgreSQL deployments has been steadily increasing over time, driven by industry trends, compliance requirements, and security-conscious best practices. However, the actual percentage can vary significantly depending on the specific use case and deployment environment.

[kenjis]

By default, RDS for PostgreSQL uses and expects all clients to connect using SSL/TLS, but you can also require it. RDS for PostgreSQL supports Transport Layer Security (TLS) versions 1.1, 1.2, and 1.3.
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/PostgreSQL.Concepts.General.SSL.html