Fix typo

[lewislbr]

The quickstart has three steps:

1. Set up a kubernetes environment
2. Install a Contour service
3. Install a kuard workload

On step 1, there is the option to skip to "Install a Contour service", which is the step 2, but is referred to as 3.

[codecov]

Codecov Report

Merging #4167 (e645cd6) into main (6d78450) will increase coverage by 0.54%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #4167      +/-   ##
==========================================
+ Coverage   73.16%   73.71%   +0.54%     
==========================================
  Files         113      114       +1     
  Lines        9884     9867      -17     
==========================================
+ Hits         7232     7273      +41     
+ Misses       2498     2440      -58     
  Partials      154      154              

Impacted Files	Coverage Δ
cmd/contour/serve.go	12.44% <0.00%> (-0.47%)	⬇️
internal/contourconfig/contourconfiguration.go	100.00% <0.00%> (ø)
pkg/config/parameters.go	92.03% <0.00%> (+0.26%)	⬆️
internal/sorter/sorter.go	98.78% <0.00%> (+1.21%)	⬆️
internal/xdscache/v3/listener.go	90.53% <0.00%> (+21.13%)	⬆️

[youngnick]

Thanks for picking this up @lewislbr!