Fix #28: Add github.token as default credential

[RammusXu]

No description provided.

[mhausenblas]

Thanks @RammusXu and WDYT @janoszen?

[ghost]

Good idea, but we should still support GITHUB_TOKEN since many have it set up that way.

[mhausenblas]

we should still support GITHUB_TOKEN since many have it set up that way.

Thanks and agreed. @RammusXu can you please change, accordingly?

[RammusXu]

I'm not sure if you want GITHUB_TOKEN > INPUT_AUTH_TOKEN > PERSONAL_TOKEN.

The only way to mess up is using GITHUB_TOKEN: ${{ secrete.PERSONAL_TOKEN }} on this PR, and it won't break existed workflow since default ${{ github.token }} should have enough permission.

Also, I think env.PERSONAL_TOKEN should be the correct way to use for existed users. So I keep it.

[mhausenblas]

Thanks for the clarification @RammusXu and I have to admit that I'm not familiar enough with the internals to object "should have enough permission" and "should be the correct way". So, unless I hear @janoszen opposing it, I'll merge ;)

[ghost]

Currently our documentation states that you can use the GITHUB_TOKEN environment variable to provide a token. Most people will map it to secrets.GITHUB_TOKEN, but that is not mandatory. I would suggest to err on the side of caution and not break the setup people already have.

Alternatively, if we are going to break something let's think of all the design choices we want to change and change it all at once.