Use brew link instead of manually symlinking ic4c
Use brew link instead of manually symlinking ic4c

Simply using `brew link` instead of manually symlinking works as well, and is probably easier to maintain. The `--force` flag is needed because the ic4c library is marked as "keg only". I verified that it worked locally by `unlink`ing the old symlinks, `brew uninstall icu4c` and running these two commands.
sbnedkov/node-icu-charset-detector,sbnedkov/node-icu-charset-detector,sbnedkov/node-icu-charset-detector,mooz/node-icu-charset-detector,mooz/node-icu-charset-detector,mooz/node-icu-charset-detector,mooz/node-icu-charset-detector,shiftkey/node-icu-charset-detector,shiftkey/node-icu-charset-detector,shiftkey/node-icu-charset-detector,sbnedkov/node-icu-charset-detector,shiftkey/node-icu-charset-detector