fix: prune detached worktrees on cleanup

These are not in any way harmful, but they are also not helpful,
and for long-standing cache directories, they can clutter things
up for no good reason.

internal/git/git.go

@@ -86,6 +86,7 @@ func (g *Git) Worktree(
  // this is just junk data in our use case, so get rid of it
  if err == nil {
  _ = os.Remove(filepath.Join(dst, ".git"))
+ _ = g.execManager.RunCmdInDir("git", []string{"worktree", "prune", "--verbose"}, cloneDir)
  }
  return err
 }

internal/git/git_public_test.go

@@ -92,6 +92,9 @@ func (suite *GitManagerPublicTestSuite) TestWorktreeOk() {
  suite.mockExec.EXPECT().
  RunCmdInDir("git", []string{"worktree", "add", "--force", suite.dstDir, suite.gitVersion}, suite.cloneDir).
  Return(nil)
+ suite.mockExec.EXPECT().
+ RunCmdInDir("git", []string{"worktree", "prune", "--verbose"}, suite.cloneDir).
+ Return(nil)
  err := suite.gm.Worktree(suite.cloneDir, suite.gitVersion, suite.dstDir)
  assert.NoError(suite.T(), err)
 }