Add the `enum_repr_variant_discriminant_changed` lint. #3108

Job	Run time
Build binary	38s
Check lint and rustfmt	17s
Build binary (Windows)	2m 51s
Semver: core-graphics	58s
Check if version changed	8s
Run tests (1.81, false)	4m 22s
Run tests (1.82, false)	4m 3s
Run tests (stable, false)	4m 4s
Run tests (beta, false)	4m 12s
Run tests (nightly, true)	8m 41s
Caching with feature config changed	27s
Semver: libp2p-dcutr 1.62.0 and libp2p-relay 0.14.0	1m 6s
Semver: libp2p-gossipsub ~0.44.0 + libp2p-request-response ~0.24.0	1m 10s
Caching across rustdoc versions	1m 29s
Semver: bevy_core v0.9.0	33s
Semver: libp2p-core 0.37.0	56s
Semver: bevy_gltf v0.9.1	58s
Semver: clap v3.2.0	47s
Semver: libp2p-uds 0.37.0	46s
Semver: dependency has warnings with "-Dwarnings" (libp2p v0.53.1)	1m 3s
Semver: ref-slice fork (git)	20s
Semver: sqllogictest v0.13.0	38s
Semver: ref-slice fork (sparse)	9s
Semver: tokio ~v1.25.0 (explicit)	2s
Semver: tokio ~v1.25.0 (implicit)	3s
Check failure when installed rustc is too old	15s
Semver: perf-event-open-sys2 v5.0.0	22s
Semver: ref-slice fork (Windows) (git)	50s
Semver: ref-slice fork (Windows) (sparse)	42s
All CI stages	1s
Check for semver compliance	0s
Run the release workflow	0s
	42m 51s

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