ci: more robust download of netmap

[catenacyber]

Link to ticket: https://redmine.openinfosecfoundation.org/issues/
None, just make CI more robust

Describe changes:

• git clone netmap instead of using actions/checkout

[jasonish]

How will we know if it helps? But, its easier to cache this way.

[catenacyber]

How will we know if it helps? But, its easier to cache this way.

If this CI fails, we know it does not help...

But please, tell me you have some better solution as this is indeed not elegant :-)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.62%. Comparing base (6ae5ae7) to head (0ab2afb).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #11903      +/-   ##
==========================================
+ Coverage   82.60%   82.62%   +0.01%     
==========================================
  Files         912      912              
  Lines      249342   249342              
==========================================
+ Hits       205968   206014      +46     
+ Misses      43374    43328      -46     

Flag	Coverage Δ
fuzzcorpus	60.68% <ø> (+0.04%)	⬆️
livemode	18.72% <ø> (+<0.01%)	⬆️
pcap	44.07% <ø> (-0.01%)	⬇️
suricata-verify	62.02% <ø> (-0.01%)	⬇️
unittests	58.94% <ø> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

[catenacyber]

Replaced by #11918