Add code style check into CI pipeline

[martinssipenko]

Adds checking of coding standard (PSR-12) as part of CI pipeline.

Resolves #18

[piotrooo]

I think you should squash similar commits with appropriate commit message.

This PR also closes #11

[martinssipenko]

I’ll rebase this if #20 is merged first. Or if this gets merged as squash, then #20 can be closed.

[NoelDavies]

Looks good!

[NoelDavies]

I Merged in #20 - You can rebase this and I can merge this in

[martinssipenko]

@NoelDavies done

[martinssipenko]

Ugh, the test are failing because #17 was merged without working CI, I'll try to fix it.

[NoelDavies]

Ah sorry mate. I'm just going through them as I can.

[martinssipenko]

@NoelDavies can you take a look at #22 and merge it?

[martinssipenko]

I'm sorry for confusion, tests are failing due to bug in guzzle in version below 6.3. I'm updating minimum guzzle version which fixes the issue.

[martinssipenko]

@NoelDavies it's now green, after merging this master branch builds will also become green.

[NoelDavies]

This would have to be a major version change as the dependency for guzzle changes.

[martinssipenko]

@NoelDavies It's a minor version change for guzzle which is backwards compatible, should also be a minor version for this package. Either way when using guzzle < 6.3 with current master it will not work, you will get the same error that was caught in tests.

[martinssipenko]

@NoelDavies can we merge this to get CI green again?

[NoelDavies]

Apologies I thought I'd merged this