switch to actions-toolkit implementation

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

src/state-helper.ts

@@ -1,6 +1,5 @@
 import * as core from '@actions/core';
 
-export const IsPost = !!process.env['STATE_isPost'];
 export const registry = process.env['STATE_registry'] || '';
 export const logout = /true/i.test(process.env['STATE_logout'] || '');
 
@@ -11,7 +10,3 @@ export function setRegistry(registry: string) {
 export function setLogout(logout: boolean) {
   core.saveState('logout', logout);
 }
-
-if (!IsPost) {
-  core.saveState('isPost', 'true');
-}