(IAC-1223) Fix clone https test

With the default branch on github for the vcsrepo module being updated from 'master' to 'main' when the module clones the default HEAD is now 'main' rather than 'master'.

Author: pmcmaw

spec/acceptance/clone_repo_spec.rb

@@ -55,7 +55,7 @@
  end
 
  describe file("#{tmpdir}/httpstestrepo/.git/HEAD") do
- it { is_expected.to contain 'ref: refs/heads/master' }
+ it { is_expected.to contain 'ref: refs/heads/main' }
  end
  end