[ci] Cargo doc step jq error

[joshlf]

In CI, this error has been happening, but not blocking merges thanks to a lack of set -e:

jq: error: syntax error, unexpected '[', expecting FORMAT or QQSTRING_START (Unix shell quoting issues?) at <top-level>, line 1:
.packages[] | select(.name == "zerocopy").metadata.docs.rs."rustdoc-args".[]                                                                          
jq: 1 compile error