Update canary MSRV to 1.86 (#1333)

<!--

IMPORTANT:

> Making changes to examples? 

Be sure to make example changes in the awsdocs/aws-doc-sdk-examples
repository (https://github.com/awsdocs/aws-doc-sdk-examples).
The examples in aws-sdk-rust are copied from the `rust_dev_preview/`
directory in that repository.


> Making changes to code?

All the code in aws-sdk-rust is auto-generated by smithy-rs
(https://github.com/awslabs/smithy-rs).
Changes to code need to be made in that repository.

-->


## Motivation and Context
<!-- Why is this change required? What problem does it solve? -->
<!-- If it fixes an open issue, please link to the issue here -->

Canary has been
[failing](https://github.com/awslabs/aws-sdk-rust/actions/runs/16556969435/job/46819914469)
due to MSRV. Updates canary to use 1.86.

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.

Author: aajtodd

.github/workflows/canary.yaml

@@ -7,7 +7,7 @@ on:
     branches:
       - "canary*"
 env:
-  tool_rust_version: 1.85.0
+  tool_rust_version: 1.86.0
   rust_nightly_version: nightly-2025-05-04
 
 jobs: