Relax requirements for devel/py-arrow

--- requirements.txt.orig	2021-08-06 12:04:59 UTC
+++ requirements.txt
@@ -1,4 +1,4 @@
-arrow>=0.8.0,<1.0.0
+arrow>=0.8.0
 importlib-metadata>=2.1.1,<3.0.0; python_version <= '3.5'
 importlib-metadata>=3.3.0; python_version > '3.5' and python_version < '3.8'
 logfury>=0.1.2,<0.2.0