Custom capacitor plugin fails with pod dependency

I’m writing my own capacitor plugin based on

https://devdactic.com/build-capacitor-plugin/

but adding it to my main project with

npm install ../MyPlugin

fails

npx cap sync

with

✖ Updating iOS native dependencies with "pod install" (may take several minutes): 
✖ update ios: 
[error] Analyzing dependencies
[!] CocoaPods could not find compatible versions for pod "MyPlugin":
  In Podfile:
    MyPlugin (from `../../../my-plugin`)

Specs satisfying the `MyPlugin (from `../../../my-plugin`)` dependency were found, but they required a higher minimum deployment target.

I tried adjusting the podfile required ios version as in

to 11 to be in line with my main project

platform :ios, '11.0'

def capacitor_pods
  # Comment the next line if you're not using Swift and don't want to use dynamic frameworks
  use_frameworks!
  pod 'Capacitor', :path => '../node_modules/@capacitor/ios'
  pod 'CapacitorCordova', :path => '../node_modules/@capacitor/ios'
end

target 'Plugin' do
  capacitor_pods
end

target 'PluginTests' do
  capacitor_pods
end

but the error still persists. Where should I look to get this going?
Thanks

Answered here ios - Custom capacitor plugin fails with pod dependency - Stack Overflow