Bump intl to 0.18.1 to make this compatible with flutter 3.10.0 and newer

[pdenert]

Is your feature request related to a problem? Please describe. I want to upgrade flutter in my project that uses stream_feed package to flutter 3.13.0. But I can't do it, because of the conflict of the intl version in stream_feed and flutter sdk:

Resolving dependencies... 
Because stream_feed >=0.4.0+1 depends on intl ^0.17.0 and [my_project] depends on intl ^0.18.1, stream_feed >=0.4.0+1 is forbidden.
So, because [my_project] depends on stream_feed ^0.6.0+2, version solving failed.

Describe the solution you'd like Bump package intl from 0.17.0 to 0.18.1

[rlee1990]

@pdenert this package isn't being supported anymore.