fix: setting upstream after creating worktree from origin branch

  ## what
  - setting upstream after creating worktree from origin branch

  ## how
  - find and replace `origin/` to `` using the `branch` variable

  ## why
  - when creating worktree from origin branch (ex `origin/branch-1`), it
    would add the upstream as `origin/origin/branch-1`
    - this will fix the duplicate origin issue

  ## where
  - ./lua/git-worktree/init.lua

  ## usage

Author: Clumsy-Coder

lua/git-worktree/init.lua

@@ -316,6 +316,7 @@ local function create_worktree(path, branch, upstream, found_branch)
         end
     })
 
+    branch = branch:gsub("origin/", "")
     local set_branch_cmd = 'git'
     local set_branch_args= {'branch', string.format('--set-upstream-to=%s/%s', upstream, branch)}
     local set_branch = Job:new({