feat: Build universal wheels (#948)

See https://packaging.python.org/guides/distributing-packages-using-setuptools/#universal-wheels

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Fixes #<issue_number_goes_here> 🦕
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..2a9acf1
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1