Timestamp instructions don't account for timezones

I've noticed that the instructions given for getting the timestamp, i.e.: https://github.com/conda-forge/conda-forge-repodata-patches-feedstock/blob/37c91e0cae27c4edb29dd833aacb5341711ddc57/recipe/pixi.toml#L19 https://github.com/conda-forge/conda-forge-repodata-patches-feedstock/blob/37c91e0cae27c4edb29dd833aacb5341711ddc57/recipe/README.md?plain=1#L206 …give the timestamp in local timezone rather than UTC, which can lead to newer packages being patched. I've worked that around locally by using `TZ=UTC` envvar, but I think a better way would be to play with `datetime` module.