fix: async not transpiled on babel for older browser

- old browser (chrome v50) gets error from the async await
- despite attempt to transpile with babel-plugin-transform-async-to-generator, it still not transpiled on my compiler
- solution is to update the codebase, since there is no value to return, might as well directly return the method result if it's a Promise

Author: chenxeed

src/FlagProvider.tsx

@@ -107,7 +107,7 @@ const FlagProvider: FC<PropsWithChildren<IFlagProvider>> = ({
     () => ({
       on: ((event, callback, ctx) => client.current.on(event, callback, ctx)) as IFlagContextValue['on'],
       off: ((event, callback) => client.current.off(event, callback)) as IFlagContextValue['off'],
-      updateContext: async (context) => await client.current.updateContext(context),
+      updateContext: (context) => client.current.updateContext(context),
       isEnabled: (toggleName) => client.current.isEnabled(toggleName),
       getVariant: (toggleName) => client.current.getVariant(toggleName),
       client: client.current,