add a version number to precompiled pyodide resources (#607)

sandbox/pyodide/Makefile

@@ -1,18 +1,26 @@
+# This number should be bumped up if making a non-additive change
+# to python packages.
+GRIST_PYODIDE_VERSION = 2
+
 default:
 	echo "Welcome to the pyodide sandbox"
 	echo "make fetch_packages  # gets python packages prepared earlier"
 	echo "make build_packages  # build python packages from scratch"
 	echo "make save_packages   # upload python packages to fetch later"
-	echo "setup  # get pyodide node package"
+	echo "make clean_packages  # remove local cache of python packages"
+	echo "setup  # get pyodide node package, and python packages"
 
 fetch_packages:
-	node ./packages.js https://s3.amazonaws.com/grist-pynbox/pyodide/packages/ _build/packages/
+	node ./packages.js https://s3.amazonaws.com/grist-pynbox/pyodide/packages/v$(GRIST_PYODIDE_VERSION)/ _build/packages/
 
 build_packages:
 	./build_packages.sh
 
 save_packages:
-	aws s3 sync _build/packages s3://grist-pynbox/pyodide/packages/
+	aws s3 sync _build/packages s3://grist-pynbox/pyodide/packages/v$(GRIST_PYODIDE_VERSION)
+
+clean_packages:
+	rm -rf _build/packages
 
 setup:
 	./setup.sh