Working pyodide build

[kylebarron]

For #77

Notes:

• You have to patch the vendored chrono version (in its cargo.toml) to 4.19 so it gets picked up correctly. Hopefully this will be unnecessary soon: 0.4.20 release planning chronotope/chrono#674
• The geopolars build works and on its own seems to load correctly within pyodide, but it fails at runtime because it tries to subclass polars and there isn't a polars pyodide wheel on pypi. See related work in Polars built in pyodide ? pola-rs/polars#3672
• To build polars, there might have to be substantial verbose changes in the series bindings because of technical issues (see error: #[ctor] is not supported on the current target when compiling for wasm32-unknown-emscripten PyO3/pyo3#2517), there can only be a single #[pymethods] implementation. So that might in effect rule out using macros. Such a change probably wouldn't be accepted as a PR into polars.
• Build steps should be the same as described in the polars issue: Polars built in pyodide ? pola-rs/polars#3672 (comment)

[djc]

FYI, chrono 0.4.20 has been released.

[kylebarron]

Thanks so much for the heads up!

[kylebarron]

stale and no longer relevant