Update release docs

[luizirber]

(they are quite outdated)

I also added pointers to update the Bioconda recipe.

Checklist

• Is it mergeable?
• make test Did it pass the tests?
• make coverage Is the new code covered?
• Did it change the command-line interface? Only additions are allowed
  without a major version increment. Changing file formats also requires a
  major version number increment.
• Was a spellchecker run on the source code and documentation after
  changes were made?

[codecov]

Codecov Report

Merging #554 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #554   +/-   ##
======================================
  Coverage    88.6%   88.6%           
======================================
  Files          30      30           
  Lines        4722    4722           
  Branches       45      45           
======================================
  Hits         4184    4184           
  Misses        536     536           
  Partials        2       2

---

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 4da4933...11191ae. Read the comment docs.

[luizirber]

Up to date with 2.2.0

Ready for review and merge @ctb