add tags to github repo code example

Example 1: git create tag and push

git tag -a v1.4 -m "my version 1.4"

Example 2: git create tag and push

$ git push origin v1.4
Counting objects: 14, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (12/12), done.
Writing objects: 100% (14/14), 2.05 KiB | 0 bytes/s, done.
Total 14 (delta 3), reused 0 (delta 0)
To git@bitbucket.com:atlasbro/gittagdocs.git
* [new tag] v1.4 -> v1.4