update WPCS to v3.0 with minor code style tweaks

[stklcode]

• update WPCS definitions to v3.0
• use printf() instead of echo sprintf()
• use __DIR__ instead of dirname( __FILE__ )
• remove unused parameter and inconsistend return value from track_visit()

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
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0.0% Duplication

[stklcode]

Apparently this was already done in b2abe7a800f3d64b10c17a88699b475325c9dd54 and the only remaining change is superseded by #286. Closing this PR.

[lloc]

• use printf() instead of echo sprintf()

Is there an advantage to using echo sprint() over printf()?

[stklcode]

No, there is no benefit in generating a formatted string and echoing the output immediately.

There is a marginal difference from the outside:

• echo sprintf(...) has no return value
• printf(...) returns the output length (we don't use it)