Fix git pull and improve upgrade

[LuernOutOfOrder]

This pull request introduces improvements to the git_pull function in src/git/mod.rs to enhance error handling and output management, along with minor adjustments to the upgrade_bin function in src/upgrade/mod.rs to reorder operations for better user feedback.

Improvements to git_pull function:

• Modified the git_pull function to use Stdio::piped() for capturing output and replaced wait() with wait_with_output() to handle both the status and output of the command. This improves error handling and provides more flexibility for processing command output. (src/git/mod.rs, src/git/mod.rsR141-R151)
• Updated imports to include Stdio from std::process to support the changes in git_pull. (src/git/mod.rs, src/git/mod.rsL1-R1)

Adjustments to upgrade_bin function:

• Reordered the git_pull call in upgrade_bin to execute before starting the throbber, ensuring that the repository pull process is clearly communicated to the user before the progress indicator begins. (src/upgrade/mod.rs, src/upgrade/mod.rsR20-R21)
• Removed and re-added the git_pull call in upgrade_bin with a new placement, aligning with the updated workflow. (src/upgrade/mod.rs, src/upgrade/mod.rsL11)