3.x: Add doOnLifecycle to Maybe, Single & Completable

[akarnokd]

Add the doOnLifecycle operator to the remaining classes.

Related #6852

[codecov]

Codecov Report

Merging #6877 into 3.x will increase coverage by 0.05%.
The diff coverage is 100%.

@@ Coverage Diff @@ ## 3.x #6877 +/- ## ============================================ + Coverage 98.21% 98.27% +0.05%  - Complexity 6525 6533 +8  ============================================ Files 733 735 +2 Lines 47054 47148 +94 Branches 6425 6432 +7 ============================================ + Hits 46214 46334 +120  + Misses 307 297 -10  + Partials 533 517 -16

Impacted Files	Coverage Δ	Complexity Δ
...rc/main/java/io/reactivex/rxjava3/core/Single.java	100% <100%> (ø)	172 <1> (+1)	⬆️
src/main/java/io/reactivex/rxjava3/core/Maybe.java	100% <100%> (ø)	200 <1> (+1)	⬆️
...in/java/io/reactivex/rxjava3/core/Completable.java	100% <100%> (ø)	130 <1> (+1)	⬆️
...3/internal/operators/maybe/MaybeDoOnLifecycle.java	100% <100%> (ø)	2 <2> (?)
...internal/operators/single/SingleDoOnLifecycle.java	100% <100%> (ø)	2 <2> (?)
...tivex/rxjava3/internal/jdk8/ParallelCollector.java	93.57% <0%> (-4.59%)	2% <0%> (ø)
...ctivex/rxjava3/internal/util/QueueDrainHelper.java	97.22% <0%> (-1.39%)	56% <0%> (-1%)
...perators/observable/ObservableMergeWithSingle.java	99.05% <0%> (-0.95%)	2% <0%> (ø)
.../operators/maybe/MaybeFlatMapIterableFlowable.java	95.9% <0%> (-0.82%)	2% <0%> (ø)
...3/internal/operators/observable/ObservableZip.java	99.31% <0%> (-0.69%)	6% <0%> (ø)
... and 19 more

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