fix: allow special server_version such as TDE

[marcofoyer]

show server_version;

server_version

15.8_TDE_1.1.8
(1 row)

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General information

We are running Cybertec Postgresql version and the server_string doesn't match for our monitoring.

Bug reports

Please include:

• RedHat 8.10
• psql (15.8_TDE_1.1.8)

Proposed changes

Sometimes it is hard for us to assess the quality of a fix.
While it may work for you, it is our job to ensure that it works for everybody.
These are some ways to help us:

• What is the expected behavior?
• What is the observed behavior?
• If it's not obvious from the above: In what way does your patch change the current behavior?
• Consider writing a unit test that would have failed without your fix.
• Is this a new problem? What made you submit this PR (new firmware, new device, changed device behavior)?

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