rust: regenerate build with cargo-raze 0.7.0 (#4292)

Summary:
Version 0.7.0 of `cargo-raze` was just released. Some visible changes:

  - can now set `[package.metadata.raze]` instead of `[raze]` to avoid a
    Cargo warning: <google/cargo-raze#274>
  - build files have been renamed and restructured to be more compliant
    with Buildifier: <google/cargo-raze#260>

If you have an old version installed, run `cargo install cargo-raze` to
update to the most recent version.

Changes to `third_party/rust/` generated with:

```
(rm -rf third_party/rust/ && cd tensorboard/data/server && cargo raze)
```

The changes to `Cargo.toml` and `third_party/rust/` are independent.

Test Plan:
Run `(cd tensorboard/data/server && cargo test)` and note that the tests
run without an “unused manifest key: raze” warning. Note further that
everything still builds with Bazel.

wchargin-branch: rust-regen-raze-0.7.0

.github/workflows/ci.yml

@@ -72,7 +72,7 @@ jobs:
     strategy:
       matrix:
         rust_version: ['1.47.0']
-        cargo_raze_version: ['0.6.1']
+        cargo_raze_version: ['0.7.0']
     steps:
       - uses: actions/checkout@v1
       - name: 'Cache Cargo home directory'

tensorboard/data/server/Cargo.toml

@@ -32,9 +32,9 @@ path = "main.rs"
 name = "rustboard_core"
 path = "lib.rs"
 
-[raze]
+[package.metadata.raze]
 workspace_path = "//third_party/rust"
 genmode = "Remote"
 
-[raze.crates.crc.'1.8.1']
+[package.metadata.raze.crates.crc.'1.8.1']
 gen_buildrs = true