Fixed cocoapods version

Summary:
Solving: https://linear.app/comm/issue/ENG-2109/versions-of-cocoapods-in-gemfilelock-and-podfilelock-dont-match
I edited Gemfile to contain >= 1.11.3 as it was already used by us in Podfile.lock.
Then I run bundle update cocoapods, so the only thing updated in Gemfile.lock is cocoapods and its dependecies.
After running pod install later on, nothing changed with Podfile.lock, so my assumption is someone already had cocoapods updated and created new Podfile.lock without updating Gemfile.

Test Plan: Build app in iOS simulator. App works in iOS simulator.

Reviewers: ashoat, tomek, atul

Reviewed By: ashoat, tomek, atul

Subscribers: abosh, atul, tomek, ashoat

Differential Revision: https://phab.comm.dev/D5474