The relevant error is this:
Undefined symbols for architecture armv7:
"_OBJC_CLASS_$_GADMediatedNativeAdNotificationSource", referenced from:
objc-class-ref in libAdapterInMobi.a(GADMAdapterInMobi.o)
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
The tutorial about InMobi is quite old, the dependencies should probably be updated.
Check their documentation:
https://support.inmobi.com/monetize/mediation-guidelines/admob/ios-admob-guidelines