ci: 🔨 allow duplicate dependencies

addresses this error linting our dependency tree:

```
error[duplicate]: found 2 duplicate entries for crate 'heck'
   ┌─ /home/katie/work/tonic/Cargo.lock:58:1
   │
58 │ ╭ heck 0.4.1 registry+https://github.com/rust-lang/crates.io-index
59 │ │ heck 0.5.0 registry+https://github.com/rust-lang/crates.io-index
   │ ╰────────────────────────────────────────────────────────────────^ lock entries
   │
   = heck v0.4.1
     └── strum_macros v0.25.3
         └── strum v0.25.0
             └── interop v0.1.0
   = heck v0.5.0
     └── prost-build v0.12.6
         ├── (build) disable-comments v0.1.0
         ├── tonic-build v0.10.2
         │   ├── (build) ambiguous_methods v0.1.0
         │   ├── codegen v0.1.0
         │   ├── (build) compression v0.1.0
         │   ├── (build) default_stubs v0.1.0
         │   ├── (build) disable-comments v0.1.0 (*)
         │   ├── (build) examples v0.1.0
         │   ├── (build) included_service v0.1.0
         │   ├── (build) integration v0.1.0
         │   ├── (build) integration-tests v0.1.0
         │   ├── (build) interop v0.1.0
         │   ├── (build) my_application v0.1.0
         │   ├── (build) root-crate-path v0.1.0
         │   ├── (build) same_name v0.1.0
         │   ├── (build) service_named_result v0.1.0
         │   ├── (build) service_named_service v0.1.0
         │   ├── (build) stream_conflict v0.1.0
         │   ├── (build) use_arc_self v0.1.0
         │   ├── (build) wellknown v0.1.0
         │   └── (build) wellknown-compiled v0.1.0
         ├── (build) uuid1 v0.1.0
         │   └── my_application v0.1.0 (*)
         └── (build) wellknown-compiled v0.1.0 (*)

advisories ok, bans FAILED, licenses ok, sources ok
```

.github/workflows/CI.yml

@@ -22,11 +22,29 @@ jobs:
     - run: cargo fmt --all --check
 
   deny-check:
+    # NOTE(kate): this allows for duplicate dependencies of a single crate.
+    # Since 0.10.2 was released, releases have drifted and `prost-build` and
+    # `strum-macros` depend on different versions of `heck`.
+    #
+    # rather than changing v0.10.2, we pass `--allow duplicate` for now, until
+    # we upgrade to [email protected].
+    #
+    # ```
+    # error[duplicate]: found 2 duplicate entries for crate 'heck'
+    #    ┌─ /home/katie/work/tonic/Cargo.lock:58:1
+    #    │
+    # 58 │ ╭ heck 0.4.1 registry+https://github.com/rust-lang/crates.io-index
+    # 59 │ │ heck 0.5.0 registry+https://github.com/rust-lang/crates.io-index
+    #    │ ╰────────────────────────────────────────────────────────────────^ lock entries
+    # ```
     name: cargo-deny check
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
     - uses: EmbarkStudios/cargo-deny-action@v1
+      with:
+        - command: check
+        - arguments: --allow duplicate
 
   codegen:
     runs-on: ubuntu-latest