improvement: Review snapshot behavior (#95)

* Improve git tag detection (#77)
* Only handle snapshot flag for release cmd (#94)
* Use core.info instead of console.log
* Update gitattributes

src/git.ts

@@ -0,0 +1,25 @@
+import * as child_process from 'child_process';
+
+const git = async (args: string[] = []) => {
+  const stdout = child_process.execSync(`git ${args.join(' ')}`, {
+    encoding: 'utf8'
+  });
+  return stdout.trim();
+};
+
+export async function isTagDirty(currentTag: string): Promise<boolean> {
+  try {
+    await git(['describe', '--exact-match', '--tags', '--match', currentTag]);
+  } catch (err) {
+    return true;
+  }
+  return false;
+}
+
+export async function getTag(): Promise<string> {
+  return await git(['describe', '--tags', '--abbrev=0']);
+}
+
+export async function getShortCommit(): Promise<string> {
+  return await git(['show', "--format='%h'", 'HEAD', '--quiet']);
+}