Rename local branch to fix action problem

Author: tautschnig

.github/workflows/update-subtree.yml

@@ -70,7 +70,7 @@ jobs:
         cd ../verify-rust-std
         git remote add rust-filtered ../rust-tmp/
         git fetch rust-filtered
-        git checkout -b update-subtree/library rust-filtered/subtree/library
+        git checkout -b subtree/library rust-filtered/subtree/library
         SUBTREE_HEAD_MSG=$(git log --format=%s -n 1 origin/subtree/library)
         UPSTREAM_FROM=$(git log --grep="${SUBTREE_HEAD_MSG}" -n 1 --format=%H rust-filtered/subtree/library)
         UPSTREAM_HEAD=$(git log --format=%H -n 1 rust-filtered/subtree/library)