update strider-git dependency for heroku's git support

Heroku have much older git:
```
$ hk run "git --version"
Running `git --version` on strider-se7ensky as run.8391:
git version 1.7.0
```
And we have an error cloning project by strider from bitbucket:
```
$ git clone --recursive git@bitbucket.com:repo/path . -b master --single-branch bitbucket 88ms -1
error: unknown option `single-branch'
```
Since this situation is fixed in newer strider-git, please update this dependency.