fix(cli): turn of `commit.gpgsign` compatibly with git v1.7.1 (#10679)

Co-authored-by: Marc Cornellà <hello@mcornella.com>

lib/cli.zsh

@@ -573,12 +573,27 @@ function _omz::pr::test {
 
     # Rebase pull request branch against the current master
     _omz::log info "rebasing PR #$1..."
-    command git rebase --no-gpg-sign master ohmyzsh/pull-$1 || {
-      command git rebase --abort &>/dev/null
-      _omz::log warn "could not rebase PR #$1 on top of master."
-      _omz::log warn "you might not see the latest stable changes."
-      _omz::log info "run \`zsh\` to test the changes."
-      return 1
+    local gpgsign
+    {
+      # Back up commit.gpgsign setting: use --local to get the current repository
+      # setting, not the global one. If --local is not a known option, it will
+      # exit with a 129 status code.
+      gpgsign=$(command git config --local commit.gpgsign 2>/dev/null)
+      [[ $? -ne 129 ]] || gpgsign=$(command git config commit.gpgsign 2>/dev/null)
+      command git config commit.gpgsign false
+
+      command git rebase master ohmyzsh/pull-$1 || {
+        command git rebase --abort &>/dev/null
+        _omz::log warn "could not rebase PR #$1 on top of master."
+        _omz::log warn "you might not see the latest stable changes."
+        _omz::log info "run \`zsh\` to test the changes."
+        return 1
+      }
+    } always {
+      case "$gpgsign" in
+      "") command git config --unset commit.gpgsign ;;
+      *) command git config commit.gpgsign "$gpgsign" ;;
+      esac
     }
 
     _omz::log info "fetch of PR #${1} successful."