gitclone: support git 2.38.1 when using submodules

See https://lore.kernel.org/lkml/xmqq4jw1uku5.fsf@gitster.g/

In the case of slapos, cloned repositories are considered trusted, so
it should not be an issue to set this flag.

CHANGELOG.rst

@@ -6,6 +6,7 @@
 ------------------
 
 - drop slapos.recipe.build:npm
+- gitclone: support git 2.38.1 when using submodules
 
 0.55 (2022-06-07)
 -----------------

slapos/recipe/build/tests.py

@@ -184,8 +184,9 @@ class GitCloneNonInformativeTests(TestCase):
       "Make sure parent repo and submodule repo are present")
     submodule_dir_main_repo = os.path.join(self.project_dir, 'dir1')
     # Add submodule to main repo and commit
-    check_call(['git', 'submodule', 'add', self.submodule_dir],
-                cwd=submodule_dir_main_repo)
+    check_call(
+      ['git', '-c', 'protocol.file.allow=always', 'submodule', 'add', self.submodule_dir],
+      cwd=submodule_dir_main_repo)
     self.gitCommit(self.project_dir, msg='Add submodule repo')
 
   def createRepositoriesAndConnect(self):

slapos/recipe/gitclone.py

@@ -196,6 +196,13 @@ class Recipe(object):
     git_clone_command = [self.git_command, 'clone',
                 self.repository,
                 self.location]
+    if not self.ignore_cloning_submodules:
+      git_clone_command = [
+        self.git_command,
+        '-c', 'protocol.file.allow=always',
+        'clone',
+        self.repository,
+        self.location]
     config = []
     if self.shared:
       git_clone_command.append('--shared')