Update gitpod image

[mahesh-panchal]

Update Gitpod image

• update nextflow version 21.10.6 -> 22.04.0
• update mamba version 0.22.1 -> 0.23.1
• remove nextflow self-update as it defeats the purpose of versioning.

PR checklist

• This comment contains a description of changes (with reason)
• CHANGELOG.md is updated
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

[codecov]

Codecov Report

Merging #1579 (df862bb) into dev (d6a4f45) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev    #1579   +/-   ##
=======================================
  Coverage   64.65%   64.65%           
=======================================
  Files          54       54           
  Lines        6253     6253           
=======================================
  Hits         4043     4043           
  Misses       2210     2210           

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