feat: allow for GitHub extended search syntax

[marwanhawari]

closes #56

• Allow multi-word search queries
• Allow the : character in search queries to allow users to use the GitHub search syntax (user:marwanhawari, language:python)

Before:

% stew search stew language:go
* Choose a GitHub project:  [Use arrows to move, type to filter]
> scala-steward-org/scala-steward [⭐️1157] :robot: A bot that helps you keep your projects up-to-date
  TheThingSystem/steward [⭐️347] The Thing System is a set of software components and network protocols that aims to fix the Internet of Things. Our steward software is written in node.js making it both portable and easily extensible. It can run on your laptop, or fit onto a small single board computer like the Raspberry Pi.
  solobat/Steward [⭐️667] A command launcher for Chrome
  marwanhawari/stew [⭐️208] 🥘 An independent package manager for compiled binaries.
  PalindromeLabs/STEWS [⭐️342] A Security Tool for Enumerating WebSockets
  lmc-eu/steward [⭐️221] PHP libraries that makes Selenium WebDriver + PHPUnit functional testing easy and robust
  rktjmp/hotpot.nvim [⭐️365] :stew: Carl Weathers #1 Neovim Plugin.

After:

% ./stew search stew language:go
* Choose a GitHub project:  [Use arrows to move, type to filter]
> marwanhawari/stew [⭐️208] 🥘 An independent package manager for compiled binaries.
  stretchr/stew [⭐️67] Stew is a very high performance package that extends common Go objects providing better alternatives or wrappers.
  deis/steward [⭐️154] The Kubernetes-native Service Broker.
  SAP/stewardci-core [⭐️18] A Kubernetes-native Jenkins pipeline execution orchestrator.
  dyrkin/zigbee-steward [⭐️15] ZigBee hub
  deis/steward-cf [⭐️4] The service controller implementation to connect Kubernetes resources to a CloudFoundry service broker
  deis/steward-framework [⭐️6] Go SDK for the Service Catalog Controller API