v2.2.1

Fix weird compile errors with D v2.104+ (#42)

AFAICT, the `typeof()` here should be superfluous, but isn't. We're
seeing errors like

…\mir-ion\source\mir\ser\package.d(529): Error: cannot implicitly convert expression `value.message` of type `const(BrowserAction)` to `serdeIgnoreOut`
…\mir-ion\source\mir\ser\package.d(1020): Error: template instance `mir.ser.serializeValueImpl!(JsonSerializer!("", Appender!(char[])), Message!(BrowserAction))` error instantiating

with D v2.104.2 and v2.105.1, that are fixed by this.