ocrd_utils: drop numpy version range,
Pillow >= 7.2.0
-# All current versions of TensorFlow require numpy < 1.19.0,
-# so make sure that now newer version is installed here.
-numpy >= 1.17.0, < 1.19.0
+# XXX explicitly do not restrict the numpy version because different
+# tensorflow versions might require different versions
+numpy
atomicwrites >= 1.3.0
