Update to ruby 2.7

[rkoster]

• Please check this box and fill the data as below once you have run the unit tests.
  Code coverage should keeps at 100%.

Changelog

• Updated ruby to 2.7.2
• Updated all gems

Please note that we where unable to update the bosh ruby package. Since this change would require access to the blobstore.
So the person merging this PR should also run:

git clone https://github.com/bosh-packages/ruby-release ~/workspace/ruby-release
cd ~/workspace/bosh-azure-cpi-release
bosh vendor-package ruby-2.7.2-r0.41.0 ~/workspace/ruby-release

Also don't forget to update the job references + cleanup references to the old ruby.

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Ruben Koster (759ad8f, 984d0a7)

[ramonskie]

this pr is depends on cloudfoundry/bosh-package-ruby-release#20

[mrosecrance]

2.7.3 was released 2 days ago and it's just that bosh vendored ruby-release version that seems to have your ruby-gems change in it.

[rkoster]

Done