Update Cargo plugin settings (#1397)

This:

* Enables `default_features` for the `tonic` dependency of the
`protoc-gen-tonic` generated code
* Enables the `file_descriptor_set` option for `prost`, which embeds the
FileDescriptorSet in the file, which is used by Tonic's reflection
implementation.

plugins/community/neoeinstein-prost/v0.3.1/buf.plugin.yaml

@@ -23,5 +23,6 @@ registry:
         # https://docs.rs/crate/prost-types/0.12.3/features
         default_features: true
   # https://github.com/neoeinstein/protoc-gen-prost/blob/protoc-gen-prost-v0.3.1/protoc-gen-prost/README.md#options
-  # No options set.
-  opts: []
+  opts:
+    # Includes the encoded FileDescriptorSet in the generated output for each module.
+    - file_descriptor_set

plugins/community/neoeinstein-tonic/v0.4.0/buf.plugin.yaml

@@ -16,8 +16,7 @@ registry:
       - name: "tonic"
         req: "0.11.0"
         # https://github.com/hyperium/tonic/blob/v0.11.0/tonic/Cargo.toml#L29
-        # The generated code does not require any of the default features of tonic.
-        default_features: false
+        default_features: true
   # https://github.com/neoeinstein/protoc-gen-prost/blob/protoc-gen-tonic-v0.4.0/protoc-gen-tonic/README.md#options
   opts:
     - no_include=true

tests/testdata/buf.build/community/neoeinstein-prost/v0.3.1/eliza/plugin.sum

@@ -1 +1 @@
-h1:JsjQgBmoYPRx2D2Qy1BNCDAH8tLofGgjZp46Lm4Aii8=
+h1:OOQTZuSd3HaGWEbX7DL5OdP7KamFOtYCWEwN8NDPrhg=

tests/testdata/buf.build/community/neoeinstein-prost/v0.3.1/petapis/plugin.sum

@@ -1 +1 @@
-h1:wJlYOc3eSFsYLteXBSvMtseQjbKBGUc2fP2dKKMZAbc=
+h1:Iz6wUNZqhHZ8tt+RtP/GB32MIBJLZ7PA0Ql+VBRYqvA=