remove --no-git option from pipeline create command

[mirpedrol]

Removing the --no-git option from nf-core create.
The argument is maintained as it is used by other commands such as sync and several tests
Close #2081

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 #2394 (4836eda) into dev (df0c1bf) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              dev    #2394      +/-   ##
==========================================
- Coverage   71.09%   71.09%   -0.01%     
==========================================
  Files          87       87              
  Lines        9410     9409       -1     
==========================================
- Hits         6690     6689       -1     
  Misses       2720     2720              

Files Changed	Coverage Δ
nf_core/__main__.py	57.07% <100.00%> (-0.07%)	⬇️