Work around Mjolnir compatibility issue by adding an import for glob_to_regex in synapse.util, where it moved from.

changelog.d/11696.misc

@@ -0,0 +1 @@
+Work around Mjolnir compatibility issue by adding an import for `glob_to_regex` in `synapse.util`, where it moved from.

synapse/util/__init__.py

@@ -31,6 +31,13 @@
 if typing.TYPE_CHECKING:
     pass
 
+# FIXME Mjolnir imports glob_to_regex from this file, but it was moved to
+#       matrix_common.
+#       As a temporary workaround, we import glob_to_regex here for
+#       compatibility with current versions of Mjolnir.
+# See https://github.com/matrix-org/mjolnir/pull/174
+from matrix_common.regex import glob_to_regex  # noqa
+
 logger = logging.getLogger(__name__)