Python requirements: switch back to released ipyxact

The development version is no longer needed, a released version is
suitable (for roughly a year now).

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/python-requirements.txt b/python-requirements.txt
index 8a394f4..a6cddc0 100644
--- a/python-requirements.txt
+++ b/python-requirements.txt
@@ -5,6 +5,7 @@
 # Keep sorted.
 gitpython
 hjson
+ipyxact >= 0.2.4
 isort
 livereload
 mako
@@ -24,10 +25,6 @@
 tabulate
 yapf
 
-# Develpment version to get around YAML parser warning triggered by fusesoc
-# Upstream tracking: https://github.com/olofk/ipyxact/issues/19
-git+https://github.com/olofk/ipyxact.git@master
-
 # Development version of edalize until all our changes are upstream
 git+https://github.com/lowRISC/edalize.git@ot