@LucasGinard Thanks for enhancing the documentation.
I've made some changes to your initial patch:

• Removed the icon from the title
  • It's our company logo, not an icon specific to this action.
• Removed the section describing compatibility
  • The compatibility for this action is simple: If you can use xcodebuild, you can use this action. I can this statement to the README, but I think it should be obvious. 😉
• Removed the section describing the action input
  • As mentioned in the description for the action input in action.yml, this is the same as xcodebuilds action parameter. So as with all other inputs, the description for it can be found in man xcodebuild. I don't want to keep this README up to date with changes to how parameters of xcodebuild works. Also, we don't do any special input validation - we just pass it on to xcodebuild.
  • I did, however, add a note about man xcodebuild to the "Inputs" section.
• I re-structured the "Examples" section into having three expandable details blocks: One for Swift packages, one for normal Xcode projects and one for workspaces. IMHO it's not required to have a special example for CocoaPods, since it simply uses workspaces.