Update DigitalOcean Firewall

Description

Update a firewall with a specified port for given IP address(es). Use option -c to fetch the current IP address of system running this program, and use it as the IP address.

Building:

• Requires Boost::program_options, Boost::json and Boost::beast

$ mkdir build && cd build
$ cmake ..
$ make

Note: Use cmake -DBOOST_ROOT=/path/to/boost_1_78_0 .. if cmake fails to find boost