rec build: stop using /sdist/ to cache rust

[Habbie]

Short description

tested with el-9 and debian-bookworm

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[coveralls]

Pull Request Test Coverage Report for Build 11973352834

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 58 unchanged lines in 12 files lost coverage.
• Overall coverage decreased (-0.009%) to 64.697%

---

Files with Coverage Reduction	New Missed Lines	%
pdns/validate.cc	1	68.42%
ext/json11/json11.cpp	1	64.49%
pdns/recursordist/lwres.cc	2	70.09%
pdns/misc.cc	2	63.6%
pdns/opensslsigners.cc	2	61.13%
pdns/remote_logger.cc	3	54.26%
pdns/iputils.cc	3	54.99%
pdns/recursordist/rec-tcp.cc	4	66.07%
pdns/signingpipe.cc	5	84.18%
pdns/recursordist/rec-tcpout.cc	6	50.79%

Totals
Change from base Build 11973306359:	-0.009%
Covered Lines:	125844
Relevant Lines:	163641

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💛 - Coveralls