🐛 Fall back to OpenXR 1.0 if XR_CURRENT_API_VERSION in unsupported

[fredemmott]

There are not yet any officially conformant 1.1 PCVR runtimes - the only two 1.1 runtimes are for Snapdragon-based devices: https://www.khronos.org/conformance/adopters/conformant-products/openxr

The code as-is will fail for most 'correct' runtimes. It will currently succeed for runtimes that either:

• have fully or partially implemented OpenXR 1.1 but not obtained official conformant status
• have not correctly implemetned the API version check

Fixes things under Meta XR Simulator.
Fixes #34

[maluoi]

You're right, this is a better strategy! This is now the second time I've fallen for this trap, sorry! I'm waffling a bit on whether openxr-explorer should go straight for XR_API_VERSION_1_0 right away, or the fallback method you use here. I think your approach might be the more interesting one here, so I'll take it, but if you have any concrete arguments one way or the other, I'd be curious to know!

Conformance list is probably behind reality, I didn't run into any issues during development with Meta's runtimes. You might be on an older version of the Meta Simulator?

[fredemmott]

Always-using XR_API_VERSION_1_0 is probably the right choice as you don't actually need any 1.1 features for OpenXR-explorer and the move to a 1.1 dependency was accidental; I went for falling back here as it was the safest, most minimal change.