Bump Rust Version in Dockerfile to 1.87 (#190)

## What does this pull request do?
Proactively bumping rust version in our Dockerfile to 1.87 to align with
our ADOT Python SDK repo:
aws-observability/aws-otel-python-instrumentation#386

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copy, and redistribute this contribution, under the terms of your
choice.

Author: yiyuan-he

Dockerfile

@@ -18,7 +18,7 @@ RUN npm install aws-aws-distro-opentelemetry-node-autoinstrumentation-$(node -p
 RUN npm install
 
 # Stage 2: Build the cp-utility binary
-FROM public.ecr.aws/docker/library/rust:1.81 as builder
+FROM public.ecr.aws/docker/library/rust:1.87 as builder
 
 WORKDIR /usr/src/cp-utility
 COPY ./tools/cp-utility .