github: move artifact and summary logic to dedicated classes

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

src/git.ts

@@ -17,7 +17,7 @@
 import * as core from '@actions/core';
 import * as github from '@actions/github';
 import {Exec} from './exec.js';
-import {GitHub} from './github.js';
+import {GitHub} from './github/github.js';
 
 export type GitContext = typeof github.context;