simple Go snapshot testing

 This package takes a snapshot of the test output and compares it to a
 snapshot committed alongside the tests. If the values don't match then
 the test will be failed.
 .
 There's no need to manually manage snapshot files: just use the
 cupaloy.SnapshotT(t, value) function in the tests and cupaloy will
 automatically find the relevant snapshot file (based on the test name)
 and compare it with the given value.