before this change, clang-tidy is triggered by a pull request. but
there are chances that user wants to retrigger it. for jenkins
jobs, user can rebuild a job manually. but for workflow, only the
developers with write permission can retrigger a workflow. this
is not convenient to regular contributors.
so, in this change, another trigger is added, so that user can
trigger the clang-tidy workflow with "/clang-tidy" command.
the syntax is inspired by IRC commands.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#20841
d484121cc8