Update lfortran version

This uses the latest lfortran where the wasm backend supports/utilizes wasi functions

Author: ubaidsk

build.sh

@@ -5,7 +5,7 @@ set -ex
 # curl https://lfortran.github.io/wasm_builds/data.json -o data.json
 #latest_commit=`curl https://lfortran.github.io/wasm_builds/dev/latest_commit`
 # Set a specific commit to use:
-latest_commit="df33df422"
+latest_commit="c969e0bc3"
 curl "https://lfortran.github.io/wasm_builds/dev/$latest_commit/lfortran.js" -o public/lfortran.js
 curl "https://lfortran.github.io/wasm_builds/dev/$latest_commit/lfortran.wasm" -o public/lfortran.wasm
 curl "https://lfortran.github.io/wasm_builds/dev/$latest_commit/lfortran.data" -o public/lfortran.data