Set a tiny CPU guarantee for all user pods

When limit is set but not guarantee, guarantee is set to match limit! For most
use cases, when we set limit but not guarantee, we want to offer no guarantee and
a limit. This doesn't seem to be possible at all (need to investigate why). In the
meantime, setting a super low guarantee here means we can guard against issues like
2i2c-org#790, where setting the limit
but not guarantee just gave users a huge guarantee, causing node spin ups to fail

Ref 2i2c-org#790

hub-templates/basehub/values.yaml

@@ -150,6 +150,14 @@ jupyterhub:
     memory:
       guarantee: 256M
       limit: 1G
+    cpu:
+      # When limit is set but not guarantee, guarantee is set to match limit! For most
+      # use cases, when we set limit but not guarantee, we want to offer no guarantee and
+      # a limit. This doesn't seem to be possible at all (need to investigate why). In the
+      # meantime, setting a super low guarantee here means we can guard against issues like
+      # https://github.com/2i2c-org/infrastructure/issues/790, where setting the limit
+      # but not guarantee just gave users a huge guarantee, causing node spin ups to fail
+      guarantee: 0.01
     networkPolicy:
       # Allow unrestricted access to the internet but not local cluster network
       enabled: true