Bump version of Sonobuoy and add new docs for v0.15.2

[johnSchnake]

No description provided.

[johnSchnake]

The doc script leaves links as sonobuoy.io/docs/... on the readme in the new version it creates. Will fixup in a followup PR; manually fixed them here.

[johnSchnake]

Also want to update the release doc to mention publishing the docs for the version at the same time as the version bump. It makes sense to put those in the same step together. We can always edit them later but no reason not to add them in the same commit.

[codecov-io]

Codecov Report

Merging #846 into master will increase coverage by 0.1%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master     #846     +/-   ##
=========================================
+ Coverage   46.57%   46.67%   +0.1%     
=========================================
  Files          75       75             
  Lines        4831     4831             
=========================================
+ Hits         2250     2255      +5     
+ Misses       2451     2448      -3     
+ Partials      130      128      -2

Impacted Files	Coverage Δ
pkg/plugin/aggregation/aggregator.go	83.2% <0%> (+4%)	⬆️

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