RPM build fix (reverted CI changes which will need to be un-reverted or made conditional) and vendor Rust dependencies to make builds much faster in any CI system.

zeroidc/vendor/serde_json/tests/ui/missing_value.stderr

@@ -0,0 +1,7 @@
+error: unexpected end of macro invocation
+ --> tests/ui/missing_value.rs:4:5
+  |
+4 |     json!({ "a" : });
+  |     ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
+  |
+  = note: this error originates in the macro `json_internal` (in Nightly builds, run with -Z macro-backtrace for more info)