### Bug or Regression

- ## Changelog
  
  ### General
  - Fix priority expander falling back to a random choice even though there is a higher priority option to choose
  - Clone `kubernetes/kubernetes` in `update-vendor.sh` shallowly, instead of fetching all revisions

`<button>`s\n  padding: $dropdown-item-padding-y $dropdown-item-padding-x;\n  clear: both;\n  font-weight: $font-weight-normal;\n  color: $dropdown-link-color;\n  text-align: inherit; // For `<button>`s\n  white-space: nowrap; // prevent links from randomly breaking onto new lines\n  background-color: transparent; // For `<button>`s\n  border: 0; // For `<button>`s\n\n  // Prevent dropdown overflow if there's no padding\n  // See https://github.com/twbs/bootstrap/pull/27703\n  @if $dropdown-padding-y...

$dropdown-item-padding-x;\n  clear: both;\n  font-weight: $font-weight-normal;\n  color: $dropdown-link-color;\n  text-align: inherit; // For `<button>`s\n  text-decoration: if($link-decoration == none, null, none);\n  white-space: nowrap; // prevent links from randomly breaking onto new lines\n  background-color: transparent; // For `<button>`s\n  border: 0; // For `<button>`s\n\n  // Prevent dropdown overflow if there's no padding\n  // See https://github.com/twbs/bootstrap/pull/27703\n  @if $dropdown-padding-y...

$dropdown-item-padding-x;\n  clear: both;\n  font-weight: $font-weight-normal;\n  color: $dropdown-link-color;\n  text-align: inherit; // For `<button>`s\n  text-decoration: if($link-decoration == none, null, none);\n  white-space: nowrap; // prevent links from randomly breaking onto new lines\n  background-color: transparent; // For `<button>`s\n  border: 0; // For `<button>`s\n\n  // Prevent dropdown overflow if there's no padding\n  // See https://github.com/twbs/bootstrap/pull/27703\n  @if $dropdown-padding-y...