Specify with homeSpan.setSketchVersion(char *).
Read back with homeSpan.getSketchVersion().
Also, MDNS now broadcasts three new fields:
hspn = HomeSpan Version
sketch = Sketch Version
ota = "yes" if OTA enabled, else "no"
These are all optional to HAP but useful if trying to keep track of version updates when using OTA and Serial Monitor is not available.