chore: add alexiscolin as gnoweb reviewer

[alexiscolin]

As I'll be leading the collective efforts around gnoweb, it would be helpful if I could be automatically pinged for any PR review related to the gnoweb folder. This PR adds my GH handle as a codeowner for this directory.

Thank you for your help!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.12%. Comparing base (641d2fd) to head (5d955a8).
Report is 7 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2967   +/-   ##
=======================================
  Coverage   61.11%   61.12%           
=======================================
  Files         565      565           
  Lines       75396    75396           
=======================================
+ Hits        46082    46087    +5     
+ Misses      25947    25942    -5     
  Partials     3367     3367           

Flag	Coverage Δ
contribs/gnodev	60.65% <ø> (-0.82%)	⬇️
contribs/gnofaucet	15.31% <ø> (+0.85%)	⬆️
gno.land	67.93% <ø> (ø)
gnovm	66.17% <ø> (ø)
misc/genstd	80.54% <ø> (ø)
misc/logos	19.88% <ø> (ø)
tm2	62.15% <ø> (+0.04%)	⬆️

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