Upgrade prettytable-rs to 0.10.0

[ichyo]

I've seen segmentation faults from cargo equip and it seems that's caused by one of dependencies prettytable-rs

Program received signal SIGSEGV, Segmentation fault.
0x00005555559d9c50 in prettytable::TableSlice::get_all_column_width ()
(gdb) where
#0  0x00005555559d9c50 in prettytable::TableSlice::get_all_column_width ()
#1  0x00005555559da3af in <prettytable::TableSlice as core::fmt::Display>::fmt ()
#2  0x00005555555ec7a2 in cargo_equip::bundle::list_packages ()
#3  0x00005555555e905b in cargo_equip::bundle ()
#4  0x00005555555e470e in cargo_equip::run ()
#5  0x00005555555c019f in cargo_equip::main ()

Since this was fixed in 0.10.0 (phsym/prettytable-rs#146), I'd like to get the library upgraded to the version.

[qryxip]

Thank you for PR! Merging.

[qryxip]

Released v0.20.0.