There are two ways to do this:
Method 1
- Go to tab
Build Settings - Flag search
inhibit_all_warnings - Set
YES
It will suppress all warnings related to the pod project. But when you do the following pod install, the flag will reset to NO.

2
podfile inhibit_all_warnings!, : ( . pod.).
platform :ios, '9.0'
inhibit_all_warnings!
target 'MyApp' do
end
: