* Update go version to 1.19.2
This commit updates the default version of go to 1.19.2. This update
includes minor security fixes for archive/tar, net/http/httputil, and
regexp packages.
For more information on the release, see: https://go.dev/doc/devel/release#go1.19.2
* Update Docker versions in CI to 20.10.17
After updating Vault to go version 1.19.2, there were several SIGABRTs
in the vault tests. These were related to a missing `pthread_create`
syscall in Docker. Since CI was using a much older version of Docker,
the fix was to bump it to latest-1 (20.10.17).
While we're at it, add a note in the developer docs encouraging the use
of the latest Docker version.
