pgvector 0.7.3 - New upstream version

Hello All,

pgvector has released 0.7.3 and I have update the packaging on Salsa [1] to
update the Debian package. I'd like to request a review and upload, as
cycles permit.

There was a build failure for sid/i386 in Salsa's CI pipeline. I suspect
this was caused by the new addition of gcc-14 to sid since the
problematic code was unchanged between 0.7.2 and 0.7.3. Reviewing the
console output from Salsa's pipeline for 0.7.2 [2], shows that gcc-13
was used for building 0.7.2. I was able to resolve the build failure by
conditionally adding -msse2 to PG_CFLAGS when DEB_HOST_ARCH is i386.

I have triggered a build on pgdg to verify that 0.7.3 successfully
builds on all support distributions and architectures.

Let me know if anything needs changes.

Thanks,

--Bradford

[1]: https://salsa.debian.org/postgresql/pgvector
[2]: https://salsa.debian.org/postgresql/pgvector/-/jobs/5850369