CLC-4062: Update gems: omniauth-cas / vcr / nokogiri / pundit / simplecov / rspec_junit_formatter

https://jira.ets.berkeley.edu/jira/browse/CLC-4062
Merge pull request #2778 from christianv/CLC-4062

CLC-4062: Update gems: omniauth-cas / vcr / nokogiri / pundit / simplecov / rspec_junit_formatter