Use stable compiler for compiling the collector

[Kobzol]

I changed it from nightly to 1.81.0 in February, but since then we bumped MSRV of the collector, so we have been running with an old collector for quite some time 🤦‍♂️ I wonder if we should error out if the compilation fails?

HEAD is now at 88542ee4 Merge pull request #2158 from Kobzol/bootstrap-disable-extended
info: syncing channel updates for '1.81.0-x86_64-unknown-linux-gnu'
1.81.0-x86_64-unknown-linux-gnu unchanged - rustc 1.81.0 (eeb90cda1 2024-09-04)
info: checking for self-update
error: rustc 1.81.0 is not supported by the following packages:
collector@0.1.0 requires rustc 1.85.0

[Mark-Simulacrum]

I think erroring could make sense though without public logs is a bit painful (needs someone privileged to debug).

[Kobzol]

We would notice a failure quite soon if no benchmarks would be running, and I can debug these things usually quite quickly, so indeed it would be useful. But let's leave it like this for now and see if the new version works.