Change ABI version to 0.2.1 (#45)
Change ABI version to 0.2.1 (#45)

This is necessary because the new proxy_get_log_level function
only exists there.

Signed-off-by: Gregory Brail <097acd6135be8192f004929e5c75bb0572ce672c@google.com>
proxy-wasm/proxy-wasm-cpp-sdk,proxy-wasm/proxy-wasm-cpp-sdk,proxy-wasm/proxy-wasm-cpp-sdk,proxy-wasm/proxy-wasm-cpp-sdk