Add two lints looking for new fields in `repr(C)` unions. #3139

Job	Run time
Build binary (Windows)	2m 23s
Build binary	39s
Check lint and rustfmt	20s
Semver: core-graphics	48s
Run tests (1.81, false)	4m 29s
Check if version changed	8s
Run tests (1.82, false)	4m 30s
Run tests (stable, false)	4m 18s
Run tests (beta, false)	4m 27s
Run tests (nightly, true)	4m 23s
Semver: bevy_core v0.9.0	28s
Check failure when installed rustc is too old	16s
Caching across rustdoc versions	1m 30s
Caching with feature config changed	25s
Semver: bevy_gltf v0.9.1	50s
Semver: clap v3.2.0	49s
Semver: libp2p-dcutr 1.62.0 and libp2p-relay 0.14.0	1m 20s
Semver: libp2p-gossipsub ~0.44.0 + libp2p-request-response ~0.24.0	1m 24s
Semver: libp2p-uds 0.37.0	1m 59s
Semver: perf-event-open-sys2 v5.0.0	18s
Semver: dependency has warnings with "-Dwarnings" (libp2p v0.53.1)	1m 18s
Semver: ref-slice fork (git)	19s
Semver: libp2p-core 0.37.0	53s
Semver: sqllogictest v0.13.0	32s
Semver: tokio ~v1.25.0 (explicit)	5s
Semver: ref-slice fork (sparse)	11s
Semver: tokio ~v1.25.0 (implicit)	2s
Semver: ref-slice fork (Windows) (git)	1m 17s
Semver: ref-slice fork (Windows) (sparse)	1m 34s
All CI stages	1s
Check for semver compliance	0s
Run the release workflow	0s
	41m 56s

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