Add repo.md with instructions for updating agent-sdk SHA (#29)

* Add repo.md with instructions for updating agent-sdk SHA

Co-authored-by: openhands <openhands@all-hands.dev>

* Move agent-SDK SHA update instructions to .openhands/microagents/repo.md

- Removed repo.md from root directory
- Added agent-SDK SHA update instructions to .openhands/microagents/repo.md
- Ran make lint successfully

Co-authored-by: openhands <openhands@all-hands.dev>

---------

Co-authored-by: openhands <openhands@all-hands.dev>

Author: malhotra5

.openhands/microagents/repo.md

@@ -27,3 +27,15 @@ When using types, prefer modern typing syntax (e.g., use `| None` instead of `Op
 - **Do NOT send summary updates in the README.md** for the repository
 - **Do NOT create .md files in the root** of the repository to track or send updates
 - Only make documentation changes when explicitly requested to
+
+## Updating Agent-SDK SHA
+
+If the user says something along the lines of "update the sha" or "update the agent-sdk sha", you need to:
+
+1. Use the `$GITHUB_TOKEN` to get the latest commit from the agent-sdk repository
+2. Update the poetry toml file with the new SHA
+3. Regenerate the uv lock file
+4. Run `./build.sh` to confirm that the build still works
+5. Open a pull request with the changes
+
+If the build fails, still open the pull request and explain what error you're seeing, and the steps you plan to take to fix it; don't fix it yet though.