Remove maxQPS from sql plugin documentation

[mantas-sidlauskas]

What changed?
Remove maxQPS from configuration example

Why?
This parameter is not supported

How did you test it?

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 01866e1a-db2a-49d7-a176-0805a0cccf9e

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 145 unchanged lines in 18 files lost coverage.
• Overall coverage increased (+0.03%) to 57.233%

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Files with Coverage Reduction	New Missed Lines	%
common/persistence/executionManager.go	2	78.89%
common/persistence/historyManager.go	2	66.67%
common/persistence/statsComputer.go	2	95.71%
common/task/weightedRoundRobinTaskScheduler.go	2	89.12%
service/matching/matcher.go	2	91.46%
common/task/fifoTaskScheduler.go	3	84.54%
service/history/task/fetcher.go	3	91.75%
common/persistence/serialization/parser.go	4	65.41%
common/persistence/serialization/thrift_decoder.go	4	61.22%
service/matching/taskListManager.go	4	78.38%

Totals
Change from base Build 01866e09-ef61-4f99-bb16-5269a1ccbd27:	0.03%
Covered Lines:	85102
Relevant Lines:	148694

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💛 - Coveralls

[mindaugasbarcauskas]

Looks good to me