Export errors with Blender 5

I'm getting a bunch of errors with Blender 5. Is this repo still maintained?

```
Python: Traceback (most recent call last):
File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/json_exporter.py", line 118, in execute
mesh = Mesh (object, scene, self)
File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/mesh.py", Line 151, in _init
recipe = BakingRecipe (bpyMesh, exporter)
File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/baking_recipe.py", line 43, in _init_
bjsMaterial = BJSMaterial (bpyMaterial, exporter)
AAAAAN/
File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/material.py", line 109, in _init_
self.bjsNodeTree = AbstractBJSNode.readMaterialNodeTree(bpyMaterial.node_tree, self.overloadChannels)
File /Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/abstract.py", line 265, in readMaterialNodeTree return AbstractBJSNode.readNodeTree(node_tree, 'ShaderNodeOutputMaterial', overloadChannels)
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File"/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/abstract.py", line 285, in readNodeTree return AbstractBJSNode(output, topLevelId, overloadChannels)
ЛАЛЛАЛЛАЛЛ
File"/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/abstract.py"
", Line 84, in _init
bjsWrapperNode = AbstractBJSNode.GetBJSWrapperNode(nodeSocket.links[O].from_node, nodeSocket.name, overloadChannels)
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File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/abstract.py"
", Line 335, in GetBJSWrapperNode
return PrincipledBJSNode(bpyNode, socketName, overloadChannels)
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File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/principled.py"
", line 25, in _init
subsurface = self.getDefault Subsurface')
ДАЛАДАЛАЛАЛА
File "/Users/casey.gibson/Library/Application Support/Blender/5.0/scripts/addons/babylon_js/materials/nodes/abstract.py"
", Line 217, in getDefault
return self.defaults [socketName]
KeyError: 'Subsurface'
```

Reproduce the export in Blender 5, starting at json_exporter.py and following the traceback through mesh.py, materials/baking_recipe.py, materials/material.py, materials/nodes/abstract.py, and materials/nodes/principled.py. Investigate the KeyError for the 'Subsurface' socket and confirm whether the exporter must accommodate Blender 5's node changes. Done means the reported material exports without this error.

Written by the indexing model from the issue text.