Allow hacking 0.6.x

We have just released hacking 0.6, this change will allow people to use
it.  Hacking 0.6 introduces several new checks, but each project has a
similar pinning so changing this won't break anything.

Change-Id: I2189e008fc6ffa8f6787070e0ee78dcdcda5586b
Merge "Allow hacking 0.6.x"