[maintainer-tools] github-merge-pr: be more conservative with git fetch

[LEDE Commits]

ansuel pushed a commit to maintainer-tools.git, branch master:
https://git.openwrt.org/e5e4154d15f6d1c178783bd5f6e5b37510d1f81c

commit e5e4154d15f6d1c178783bd5f6e5b37510d1f81c
Author: Christian Marangi <ansuelsmth at gmail.com>
AuthorDate: Thu Nov 2 20:36:06 2023 +0100

    github-merge-pr: be more conservative with git fetch
    
    Be more conservative with git fetch and fetch only the require branch
    for both origin and PR branch.
    
    This should speedup git fetch and save on disk space as only the
    required history and changes are downloaded.
    
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
---
 github-merge-pr.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/github-merge-pr.sh b/github-merge-pr.sh
index 191a5b1..863d3b7 100755
--- a/github-merge-pr.sh
+++ b/github-merge-pr.sh
@@ -65,7 +65,7 @@ fi
 
 echo "Pulling current $BRANCH from origin"
 $GIT checkout $BRANCH
-$GIT fetch origin
+$GIT fetch origin $BRANCH
 
 if ! $GIT rebase origin/$BRANCH; then
 	echo "Failed to rebase $BRANCH with origin/$BRANCH" >&2
@@ -83,7 +83,7 @@ if ! $GIT remote get-url $PR_USER &> /dev/null || [ -n "$DRY_RUN" ]; then
 fi
 
 echo "Fetching remote $PR_USER"
-$GIT fetch $PR_USER
+$GIT fetch $PR_USER $PR_BRANCH
 
 if [ "$(echo "$PR_INFO" | jq -r ".maintainer_can_modify")" == "true" ]; then
 	echo "Creating branch $LOCAL_PR_BRANCH for $PR_BRANCH"