[ArtifactHub.io] GPG public key annotation added

[didierofrivia]

Part of the work needed for Kuadrant/helm-charts#18

This PR adds a new annotation in the Helm Chart.yaml meant for displaying the public key used for signing its chart packages. More info in https://artifacthub.io/docs/topics/annotations/helm/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.45%. Comparing base (42d065f) to head (d97e8dd).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1155      +/-   ##
==========================================
+ Coverage   83.37%   83.45%   +0.07%     
==========================================
  Files          81       81              
  Lines        6943     6943              
==========================================
+ Hits         5789     5794       +5     
+ Misses        928      925       -3     
+ Partials      226      224       -2     

Flag	Coverage Δ
bare-k8s-integration	22.87% <ø> (+0.18%)	⬆️
controllers-integration	74.94% <ø> (ø)
envoygateway-integration	40.59% <ø> (+0.23%)	⬆️
gatewayapi-integration	19.55% <ø> (+1.07%)	⬆️
istio-integration	43.16% <ø> (-0.22%)	⬇️
unit	19.57% <ø> (ø)

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

Components	Coverage Δ
api/v1beta1 (u)	90.00% <ø> (ø)
api/v1beta2 (u)	∅ <ø> (∅)
pkg/common (u)	∅ <ø> (∅)
pkg/istio (u)	62.06% <ø> (ø)
pkg/log (u)	93.18% <ø> (ø)
pkg/reconcilers (u)	24.67% <ø> (ø)
pkg/rlptools (u)	∅ <ø> (∅)
controllers (i)	86.78% <ø> (+0.15%)	⬆️

see 5 files with indirect coverage changes