Ensure-pip: force refreshing yum/dnf cache

In some cases the cache is not so old but new packages already landed in
the repository, making it impossible to install some now outdated
packages.

Adding `update_cache: yes` allows to force refreshing yum/dnf's cache
before trying to install packages.

Change-Id: Id478271edc03e7556cbdff8bbf906efc6a1af84e
1 file changed
tree: 49bf877a122dec0e21ee5583261f60bb4c4d37dc
  1. .gitreview
  2. README
  3. playbooks/
  4. roles/
  5. zuul.d/