Initial Tests & CI (#5)

* Added awscrt_version() and test for it

* Added builder.json for CI

* Added github actions

* Added format-check.sh

* Force php5.6 on ubuntu

* Updated submodules

tests/awscrt_000.phpt

@@ -0,0 +1,15 @@
+--TEST--                                 
+Version: Simple function call
+--SKIPIF--
+<?php
+require_once(dirname(__FILE__) . '/skipif.inc');
+?>
+--FILE--
+<?php
+require_once(dirname(__FILE__) . '/common.inc');
+
+echo awscrt_version();
+?>
+===DONE===
+--EXPECT--
+1.0.0-dev

tests/common.inc

@@ -0,0 +1,3 @@
+<?php
+// Common setup for tests:
+?>

tests/skipif.inc

@@ -0,0 +1,3 @@
+<?php
+    extension_loaded('awscrt') or die('awscrt is not available in this build');
+?>