L2SS-698: Reduce numpy version requirement

tangostationcontrol/requirements.txt

@@ -14,5 +14,5 @@ python-logstash-async >= 2.3.0 # MIT
 python-casacore >= 3.3.1 # LGPLv3
 etrs-itrs@git+https://github.com/brentjens/etrs-itrs # license pending
 # numpy must be manually added even though etrs-itrs requires it
-numpy >= 1.22.0 # BSD
+numpy >= 1.21.0 # BSD
 lofarantpos >= 0.5.0 # Apache 2