Switch to vcpkg for dependencies.

Ubuntu ships very old versions and it's cramping my style.
(In particular, I want to be able to use Abseil logging.)

While I'm here, add GCC 14 to the build matrix.

... and remove GCC 11 so that we continue to
test with only the three most recent releases.

Change-Id: If7eb226005d8d9e56d3523e6e255d29814646d10
Reviewed-on: https://code-review.googlesource.com/c/re2/+/63070
Reviewed-by: Alex Chernyakhovsky <achernya@google.com>
Reviewed-by: Paul Wankadia <junyer@google.com>
2 files changed