for some reasons, tests expect the default branch to be called 'main',
while on alpine it's still 'master'.

to fix this, we can just rename the branch after cloning a test repo to 'main'.

--- a/Makefile
+++ b/Makefile
@@ -596,6 +596,7 @@ test : fmt $(.DEFAULT_GOAL)
 		tempdir="$$(mktemp -d)"; \
 		export HOME="$$tempdir"; \
 		export GIT_CONFIG_NOSYSTEM=1; \
+		git config --global init.defaultBranch main; \
 		$(GO) test -count=1 $(GO_TEST_EXTRA_ARGS) $(addprefix ./,$(PKGS)); \
 		RET=$$?; \
 		chmod -R u+w "$$tempdir"; \
--- a/t/testhelpers.sh
+++ b/t/testhelpers.sh
@@ -439,6 +439,7 @@ clone_repo() {
   fi
 
   cd "$dir"
+  git branch -m main
   mv ../clone.log .
 
   git config credential.helper lfstest
@@ -459,6 +460,7 @@ clone_repo_url() {
   fi
 
   cd "$dir"
+  git branch -m main
   mv ../clone.log .
 
   git config credential.helper lfstest
@@ -633,6 +635,8 @@ setup() {
   # setup the git credential password storage
   setup_creds
 
+  git config --global init.defaultBranch main
+
   echo "#"
   echo "# HOME: $HOME"
   echo "# TMP: $TMPDIR"