update llfuse requirements, llfuse 1.3.8 is out!

requirements.d/fuse.txt

@@ -1,4 +1,3 @@
 # low-level FUSE support library for "borg mount"
 # please see the comments in setup.py about llfuse.
-llfuse >=1.3.4, <1.3.7; python_version <"3.9"  # broken on py39
-llfuse >=1.3.7, <2.0; python_version >="3.9"  # broken on freebsd
+llfuse >=1.3.4

setup.py

@@ -41,13 +41,10 @@ install_requires = []
 # if you do not have llfuse, do not require it, most of borgbackup will work.
 extras_require = {
     'fuse': [
-        # note: the C code generated by cython and bundled into the pypi package
-        # is the reason for these requirements. Pre-1.3.7 it was made by a too old
-        # cython to work on py39. In 1.3.7 it was made by a cython version that
-        # produces py39 compatible code, but that also led to a freebsd compile issue.
-        # if you cythonize yourself, you can use either version.
-        'llfuse >=1.3.4, <1.3.7; python_version <"3.9"',  # broken on py39
-        'llfuse >=1.3.7, <2.0; python_version >="3.9"',  # broken on freebsd
+        # 1.3.8 is the fixed version that works on py39 AND freebsd.
+        # if you cythonize yourself and make sure llfuse works for your
+        # OS and python version, you can use other versions than 1.3.8, too.
+        'llfuse >=1.3.4',  # should nowadays pull 1.3.8 or better
     ],
 }