• Update to the latest config version
• Change the build folder to "${workspaceRoot}/build"
• Add option to control cmake build type
• Add new task to push current branch to gerrit

Change-Id: I0465bec244ebc06fd7f0f460f5673ed666077a1d
Reviewed-on: https://swiftshader-review.googlesource.com/c/24468
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>