Help with old version of Cocoapods

[jerryhamby]

If this is not the right place for this question please direct me.
I definitely need help.

I have Cocoapods 1.8.4 on my iMac and need to upgrade to the latest version. 
I need help…

Every time I have tried, I keep running into the same problem:
[!] Xcode - develop for iOS and macOS
! CocoaPods 1.8.4 out of date (1.10.0 is recommended).
CocoaPods is used to retrieve the iOS and macOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without CocoaPods, plugins will not work on iOS or macOS.
For more info, see https://flutter.dev/platform-plugins
To upgrade see https://guides.cocoapods.org/using/getting-started.html#installation for instruction

======== Here is the error ========
Function.c:867:17: error: implicit declaration of function 'ffi_prep_closure_loc' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
ffiStatus = ffi_prep_closure_loc(closure->pcl, &fnInfo->ffi_cif, callback_invoke, closure, code);
^
Function.c:867:17: note: did you mean 'ffi_prep_closure'?
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/ffi/ffi.h:269:1: note: 'ffi_prep_closure' declared here
ffi_prep_closure(
^
1 error generated.