ci: Trigger actions on pull requests to rc/v* branches (#5626)

[mofojed]

• With new rc/v* branches created, we need the actions to run on those branches as well

[devinrsmith]

I believe we'll need to merge in #5621 if we want CI to pass here:

 ======================================================================
ERROR [1.035s]: test_agg_with_options (test_table.TableTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/project/tests/test_table.py", line 335, in test_agg_with_options
    aggs = [unique(cols=["ua = a", "ub = b"], include_nulls=True, non_unique_sentinel=np.uint32(-1))]
OverflowError: Python integer -1 out of bounds for uint32