Add Readme Bindings Update Note (#188)

## 📔 Objective

Add a note about not editing the `Cargo.toml` file when doing a bindings
update PR.

## ⏰ Reminders before review

- Contributor guidelines followed
- All formatters and local linters executed and passed
- Written new unit and / or integration tests where applicable
- Protected functional changes with optionality (feature flags)
- Used internationalization (i18n) for all UI strings
- CI builds passed
- Communicated to DevOps any deployment requirements
- Updated any necessary documentation (Confluence, contributing docs) or
informed the documentation
  team

## 🦮 Reviewer guidelines

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- 👍 (`:+1:`) or similar for great changes
- 📝 (`:memo:`) or ℹ️ (`:information_source:`) for notes or general info
- ❓ (`:question:`) for questions
- 🤔 (`:thinking:`) or 💭 (`:thought_balloon:`) for more open inquiry
that's not quite a confirmed
  issue and could potentially benefit from discussion
- 🎨 (`:art:`) for suggestions / improvements
- ❌ (`:x:`) or ⚠️ (`:warning:`) for more significant problems or
concerns needing attention
- 🌱 (`:seedling:`) or ♻️ (`:recycle:`) for future improvements or
indications of technical debt
- ⛏ (`:pick:`) for minor or nitpick changes

Author: coltonhurst

README.md

@@ -93,8 +93,12 @@ This project uses customized templates which lives in the `support/openapi-templ
 These templates resolves some outstanding issues we've experienced with the rust generator. But we
 strive towards modifying the templates as little as possible to ease future upgrades.
 
-Note: If you don't have the nightly toolchain installed, the `build-api.sh` script will install it
-for you.
+### Note
+
+- If you don't have the nightly toolchain installed, the `build-api.sh` script will install it for
+  you.
+- This process also changes the `Cargo.toml` file. When creating a PR updating the bindings, please
+  revert (do not include) the updates to the `Cargo.toml` file.
 
 ## Developer tools