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

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update db0bd71...e045765. Read the comment docs.