DOC Add deprecation timeline (#2314)

* Add deprecation timeline [skip ci]

* Add pyodide-interrupts removal

docs/project/changelog.md

@@ -1005,3 +1005,10 @@ _Mar 21, 2019_
   have been removed.
 
 - The `run_docker` script can now be configured with environment variables.
+
+```{eval-rst}
+.. toctree::
+   :hidden:
+
+   deprecation-timeline.md
+```

docs/project/deprecation-timeline.md

@@ -0,0 +1,32 @@
+(deprecation-timeline)=
+
+# Pyodide Deprecation Timeline
+
+Each Pyodide release may deprecate certain features from previous releases in a backward incompatible way.
+If a feature is deprecated, it will continue to work until its removal, but raise warnings.
+We try to ensure deprecations are done over at least two minor(feature) releases,
+however, as Pyodide is still in beta state, this list is subject to change and
+some features can be removed without deprecation warnings.
+More details about each item can often be found in the {ref}`changelog`.
+
+## 0.21.0
+
+- The `globals` argument to `runPython` and `runPythonAsync` will be passed as a named argument only.
+
+## 0.20.0
+
+- The skip-host key will be removed from the meta.yaml format. If needed, install a host copy of the package with pip instead.
+- `pyodide-interrupts` module will be removed. If you were using this for some reason, use
+  {any}`setInterruptBuffer <pyodide.setInterruptBuffer>` instead.
+
+## 0.19.0
+
+- The default working directory (home directory) inside the Pyodide
+  virtual file system has been changed from `/` to `/home/pyodide`. To get the
+  previous behavior, you can
+
+  - call `os.chdir("/")` in Python to change working directory or
+  - call {any}`loadPyodide <globalThis.loadPyodide>` with the `homedir="/"`
+    argument
+
+- When a JavaScript function is called from Python, PyProxy arguments and return values will be automatically destroyed when the function is finished.