sig-exec: promote b41sh to committer

[qw4990]

Since @b41sh has contributed a lot to sig-exec, according to sig-exec roles-and-organization-management.md#promotion, we would like to promote him to our new committer, and his detailed contribution is shown below:

1. contribute 40+ PRs to the executor,
2. using go template to vectorized 24+ builtin functions (a medium task),
3. support variable-setting hint SET_VAR (a medium task),
4. implement the framework of tracing AggFun memory and help other contributors add memory trace for all aggregation functions (a hard task),
5. help other contributors and review 25+ PRs.

Thanks for his contribution!! 😃 🎊

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ qw4990
❌ shenli
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[qw4990]

PTAL @SunRunAway @winkyao @AndreMouche

[zz-jason]

LGTM

[winkyao]

LGTM, congratulation.

[jackysp]

LGTM

[shenli]

LGTM