Add Clang 14 to the build matrix.

Change-Id: Ica7816a3473512a2d317338c40e1305f4818e498
Reviewed-on: https://code-review.googlesource.com/c/re2/+/59810
Reviewed-by: Justin Lebar <jlebar@google.com>
Reviewed-by: Paul Wankadia <junyer@google.com>
1 file changed