Add SKILL.md for updating azure_core/azure_identity (microsoft#742)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: johnbatty

SKILL.md

@@ -0,0 +1,79 @@
+# Updating azure_core and azure_identity
+
+## Overview
+
+The `azure_devops_rust_api` crate depends on `azure_core` (runtime) and `azure_identity` (dev/examples). These are updated periodically to track the latest Azure SDK for Rust releases.
+
+## Process
+
+### 1. Find the latest versions
+
+Check crates.io for the latest versions. They are released in lockstep and should use the same version.
+- https://crates.io/crates/azure_core
+- https://crates.io/crates/azure_identity
+
+Watch out for yanked versions (e.g. 0.30.0 was yanked, 0.30.1 replaced it).
+
+### 2. Update version strings
+
+Edit `azure_devops_rust_api/Cargo.toml`:
+- `azure_core = { version = "X.Y", ... }` in `[dependencies]`
+- `azure_identity = "X.Y"` in `[dev-dependencies]`
+
+### 3. Build and fix
+
+```sh
+cargo check --all-features
+cargo check --all-features --examples
+```
+
+If there are no compilation errors, you're done with code changes.
+
+If there are errors, fixes may be needed in two places:
+
+**Code generator** (for generated code errors — do NOT edit generated files directly):
+- `autorust/codegen/src/codegen_operations/create_client_and_builder.rs` — Pipeline, Transport, RetryOptions usage
+- `autorust/codegen/src/codegen_operations/request_builder_send.rs` — Pipeline::send() calls, api-version parameter
+- `autorust/codegen/src/codegen_operations/request_builder_into_future.rs` — into_body()/into_model() calls
+- `autorust/codegen/src/codegen_operations/response_code.rs` — Response type definitions
+
+After fixing codegen, regenerate with `./build.sh`, then re-check.
+
+**Hand-written source** (fix directly):
+- `azure_devops_rust_api/src/auth.rs` — TokenCredential, error handling
+- `azure_devops_rust_api/src/date_time.rs` — error handling
+- `azure_devops_rust_api/src/telemetry.rs` — Policy trait, Response types
+
+### 4. Update CHANGELOG.md
+
+Add an entry under `## [Unreleased]`:
+
+```markdown
+### Changes
+
+- Update `azure_core` and `azure_identity` to X.Y.
+```
+
+If code changes were needed, list them (see the 0.33.0 entry for a detailed example).
+
+### 5. Branch, commit, push
+
+```sh
+git checkout -b azure_core-X.Y
+git add CHANGELOG.md azure_devops_rust_api/Cargo.toml [any other changed files]
+git commit -m "Update azure_core, azure_identity to X.Y"
+git push -u origin azure_core-X.Y
+```
+
+The README (`azure_devops_rust_api/README.md`) version string is only updated at release time, not during dependency updates.
+
+## Key azure_core types used by this crate
+
+These are the areas most likely to break across versions:
+- `azure_core::http::Pipeline` — HTTP pipeline for sending requests
+- `azure_core::http::Request` / `RawResponse` — request/response types
+- `azure_core::http::RetryOptions` / `Transport` — client configuration
+- `azure_core::http::Context` — request context
+- `azure_core::http::policies::Policy` — pipeline policies (telemetry.rs)
+- `azure_core::credentials::TokenCredential` — authentication (auth.rs)
+- `azure_core::error::{Error, ErrorKind, Result}` — error types