Adding support for Github API key #157

[dhruvinsh]

resolves #157

[dhruvinsh]

@MordechaiHadad First time trying rust lang. Please take a look at implementation and it works as expected for me.

Usage (one of the example):

GITHUB_TOKEN=<your token> bob update -a

or as normal usage,

bob update -a

[MordechaiHadad]

Also if you can, add to the readme that it is possible to add ur github token to be used with bob

[dhruvinsh]

Also if you can, add to the readme that it is possible to add ur github token to be used with bob

done.

[MordechaiHadad]

Also if you can, add to the readme that it is possible to add ur github token to be used with bob

done.

Move it to configuration part in the README, and test if it works correctly if the env var doesn't exist.
after that it is ready for merge!

[dhruvinsh]

Move it to configuration part in the README

Done with more detail. Feel free to update the way you like it if I am missing anything here.

test if it works correctly if the env var doesn't exist.

Tried it on my rate-limit network and works as expected.

~/Documents/bob on  github-api is 📦 v2.6.0 via 🦀 v1.73.0 
➜ cargo build && ./target/debug/bob update -a
    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
Nov 08 10:11:23.177  INFO Fetching latest version
Nov 08 10:11:23.320 ERROR Error: invalid type: map, expected a sequence at line 1 column 0

~/Documents/bob on  github-api is 📦 v2.6.0 via 🦀 v1.73.0 
➜ GITHUB_TOKEN=<some token> cargo run update -a
    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
     Running `target/debug/bob update -a`
Nov 08 10:11:30.382  INFO Fetching latest version
Nov 08 10:11:31.095  INFO Looking for nightly updates
Nov 08 10:11:31.096  INFO Nightly is already updated!

[MordechaiHadad]

Beautiful, thank you @dhruvinsh