Update DEPLOY.md with pyodide instructions

DEPLOY.md

@@ -61,3 +61,18 @@ The release cycle should be performed like this:
    3. Propose merge-request.
    4. Check CI succeeds.
    5. Accept merge and the new version will be uploaded.
+
+8. Update pyodide version
+
+   Until web assembly (wasm) wheels are supported by PyPi, they
+   are managed directly in the pyodide repository. The update steps
+   are very similar to conda, except all packages are managed
+   in a single repository. The meta.yaml is at packages/sisl/meta.yaml.
+   Follow these steps:
+
+   1. branch off https://github.com/pyodide/pyodide
+   2. Edit packages/sisl/meta.yaml by updating version, source url and sha256
+   3. Propose merge-request.
+   4. Check CI succeeds. If it doesn't you can test locally by following
+      instructions [here](https://pyodide.org/en/stable/development/new-packages.html#building-a-python-package-in-tree)
+   5. Wait for the pyodide team to accept your request.