Add Clang 16 to the build matrix.

... and remove Clang 13 so that we continue to
test with only the three most recent releases.

Change-Id: I0ee7e7f252e364d641430ba6c99270d858f70e73
Reviewed-on: https://code-review.googlesource.com/c/re2/+/61190
Reviewed-by: Perry Lorier <perryl@google.com>
Reviewed-by: Paul Wankadia <junyer@google.com>
1 file changed