Added support for GPG

src/gpg.ts

@@ -0,0 +1,58 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import * as io from '@actions/io';
+import * as exec from '@actions/exec';
+import * as util from './util';
+import {ExecOptions} from '@actions/exec/lib/interfaces';
+
+export const PRIVATE_KEY_FILE = path.join(util.getTempDir(), 'private-key.asc');
+
+const PRIVATE_KEY_FINGERPRINT_REGEX = /\w{40}/;
+
+export async function importKey(privateKey: string) {
+  fs.writeFileSync(PRIVATE_KEY_FILE, privateKey, {
+    encoding: 'utf-8',
+    flag: 'w'
+  });
+
+  let output = '';
+
+  const options: ExecOptions = {
+    silent: true,
+    listeners: {
+      stdout: (data: Buffer) => {
+        output += data.toString();
+      }
+    }
+  };
+
+  await exec.exec(
+    'gpg',
+    [
+      '--batch',
+      '--import-options',
+      'import-show',
+      '--import',
+      PRIVATE_KEY_FILE
+    ],
+    options
+  );
+
+  await io.rmRF(PRIVATE_KEY_FILE);
+
+  const match = output.match(PRIVATE_KEY_FINGERPRINT_REGEX);
+  return match && match[0];
+}
+
+export async function deleteKey(keyFingerprint: string) {
+  await exec.exec(
+    'gpg',
+    ['--batch', '--yes', '--delete-secret-keys', keyFingerprint],
+    {silent: true}
+  );
+  await exec.exec(
+    'gpg',
+    ['--batch', '--yes', '--delete-keys', keyFingerprint],
+    {silent: true}
+  );
+}