update rust-vmm-ci anchor

This update brings the following commits:

e58ea74 Fix kcov_ouput_dir typo in test_coverage.py
d62d781 fix buildkite typos in readme
0fc8ced refactor test_benchmark.py
741b894 checkout to PR branch before finishing test_bench
645a5c3 test_bench: don't crash when no bench on master
bd32544 Fetch origin in benchmark test
35beb91 Fix commit message test
53427aa benchmarks: add test that can run at every PR
abd2c90 Add test for commit message format
fe859f4 Update container image to v6
75d7254 run cargo check on all features
7e3f307 skip coverage-arm test
cd7096e Enable rust-vmm coverage test in CI

Signed-off-by: Alexandru Agache <[email protected]>

Author: alexandruag