maint(ci): skip archlinux SAGE job in GA

For now the archlinux job fails too often for reasons unrelated to
SAGE's use of SymPy so we skip Arch and only test Ubuntu. The
ubuntu-focal job also fails sometimes due to timeouts or network
problems but it mostly succeeds and does correctly pick up where a
change in SymPy affects SAGE. Mostly this is where there are printing
changes in SymPy because SAGE does most of its testing in the form of
doctests.

Author: oscarbenjamin

.github/workflows/ci-sage.yml

@@ -95,7 +95,17 @@ jobs:
       matrix:
         # ubuntu-focal uses system python 3.8
         # archlinux-latest is at the cutting edge
-        tox_system_factor: [ubuntu-focal, archlinux-latest]
+        #
+        # XXX: For now the archlinux job fails too often for reasons unrelated
+        # to SAGE's use of SymPy so we skip Arch and only test Ubuntu. The
+        # ubuntu-focal job also fails sometimes due to timeouts or network
+        # problems but it mostly succeeds and does correctly pick up where a
+        # change in SymPy affects SAGE. Mostly this is where there are printing
+        # changes in SymPy because SAGE does most of its testing in the form of
+        # doctests.
+        #
+        #tox_system_factor: [ubuntu-focal, archlinux-latest]
+        tox_system_factor: [ubuntu-focal]
         # "standard" installs lots of system packages, reducing the full build and test of the
         # Sage distribution to 3-4 hours
         tox_packages_factor: [standard]