v0.3.0

Modifications:

• added next() as a method to return reference to new SubmissionEntry
• added submitAndWait to optimize out some unnecessary branches
• added flush that just adjusts index visible by kernel (useable when kernel itself is polling the queue)
• update to latest Linux kernel 5.15 changes including helper functions to setup operations
• changed methods to work with provided buffers (5.7)
• switch to github actions
• some additional small fixes and tweaks
• removed static assert for unsupported platform using just version (linux) to hide the implementation for them
• changed prep methods to allow new chain syntax:

io.next
    .prepRecv(ctx.fd, grid, len)
    .setUserDataRaw(someData)
    .flags |= SubmissionEntryFlags.BUFFER_SELECT;

• added probe methods (static and directly on Uring instance) to check what operations kernel actually supports (available from 5.6)

auto prob = probe(); // creates temporary uring instance
assert(prob);
assert(prob.error == 0);
assert(prob.isSupported(Operation.RECV));

Fixes:

• fixed enum member name to be on par with the others
• some minor fixes