Doesn't build on MacOS

[miketweaver]

This doesn't build on MacOS.

[ 52%] Building CXX object CMakeFiles/gplaydl.dir/lib/playapi/experiments.cpp.o
[ 54%] Building CXX object CMakeFiles/gplaydl.dir/lib/playapi/util/http.cpp.o
[ 57%] Building CXX object CMakeFiles/gplaydl.dir/lib/playapi/util/config.cpp.o
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:83:16: error: invalid operands to binary expression ('std::ostream' (aka 'basic_ostream<char>') and 'int')
        stream << '"' << std::regex_replace(value, escape_val_regex, "\\$&") << '"';
        ~~~~~~ ^  ~~~
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:5430:1: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-2>' against 'char'
operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p);
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/string:4167:1: note: candidate template ignored: could not match 'basic_string<type-parameter-0-0, type-parameter-0-1, type-parameter-0-2>' against 'char'
operator<<(basic_ostream<_CharT, _Traits>& __os,
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/regex:5165:1: note: candidate template ignored: could not match 'sub_match<type-parameter-0-2>' against 'char'
operator<<(basic_ostream<_CharT, _ST>& __os, const sub_match<_BiIter>& __m)
^
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:90:12: error: value of type 'basic_istream<char, std::__1::char_traits<char> >' is not contextually convertible to 'bool'
    while (std::getline(stream, line)) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:96:17: error: invalid argument type 'basic_istream<char, std::__1::char_traits<char> >' to unary expression
            if (!std::getline(stream, tmp_line))
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:107:12: error: value of type 'std::istream' (aka 'basic_istream<char>') is not contextually convertible to 'bool'
    while (read_line(stream, line)) {
           ^~~~~~~~~~~~~~~~~~~~~~~
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:119:21: error: invalid argument type 'std::istream' (aka 'basic_istream<char>') to unary expression
                if (!read_line(stream, line))
                    ^~~~~~~~~~~~~~~~~~~~~~~~
/Users/users/Google-Play-API/lib/playapi/util/config.cpp:141:73: error: invalid operands to binary expression ('basic_ostream<char, std::__1::char_traits<char> >' and 'const char *')
        stream << std::regex_replace(e.first, escape_key_regex, "\\$&") << " = ";
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:5430:1: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-2>' against 'char const[4]'
operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p);
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/string:4167:1: note: candidate template ignored: could not match 'basic_string<type-parameter-0-0, type-parameter-0-1, type-parameter-0-2>' against 'char const[4]'
operator<<(basic_ostream<_CharT, _Traits>& __os,

Adding #include <iostream>
to lib/playapi/util/config.cpp fixes it.