Fix pyglet version pin to exclude incompatible 3.0 pre-release

[Kripner]

Pin pyglet>=2.1.6,<3.0 in source/isaaclab/setup.py to prevent pip/uv from resolving to pyglet==3.0.dev2, which removes pyglet.graphics.shader.Shader and breaks the Newton OpenGL viewer.

Test of the fix: Newton visualizer launches without ImportError: ./isaaclab.sh -p scripts/environments/zero_agent.py --task Isaac-Reach-Franka-v0 --num_envs 4 env.sim.physics=newton --visualizer newton

[greptile-apps]

Greptile Summary

This PR tightens the pyglet version pin in source/isaaclab/setup.py from >=2.1.6 to >=2.1.6,<3.0 to prevent pip/uv from resolving to pyglet==3.0.dev2, which dropped pyglet.graphics.shader.Shader and broke the Newton OpenGL viewer. The change is minimal, correct, and consistent with how PEP 440 exclusive upper-bound comparisons exclude pre-releases of the boundary version.

Confidence Score: 5/5

• Safe to merge — single-line dependency pin with a confirmed fix for a broken install path.
• The only change is narrowing a version range for a single dependency. The fix is correct per PEP 440 (exclusive <3.0 blocks 3.0.dev2 and the whole 3.x pre-release series), has been manually verified by the author, and no other setup files need updating. The sole finding is a P2 documentation suggestion.
• No files require special attention.

Important Files Changed

Filename	Overview
source/isaaclab/setup.py	Narrows the pyglet version specifier from >=2.1.6 to >=2.1.6,<3.0, correctly blocking pyglet==3.0.dev2 (and the entire 3.x line) which removed pyglet.graphics.shader.Shader and broke the Newton OpenGL viewer.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[pip / uv resolves pyglet] --> B{Version satisfies constraint?}
    B -- "Before: >=2.1.6" --> C["pyglet==3.0.dev2 ✓ (pre-release selected)"]
    B -- "After: >=2.1.6,<3.0" --> D["pyglet==3.0.dev2 ✗ (excluded by PEP 440 <3.0)"]
    C --> E["ImportError: pyglet.graphics.shader.Shader missing"]
    D --> F["Latest 2.x release installed ✓"]
    F --> G["Newton OpenGL viewer launches correctly ✓"]

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_{Reviews (1): Last reviewed commit: "Fix pyglet version pin to exclude incomp..." | Re-trigger Greptile}

[isaaclab-review-bot]

Clean, minimal fix. The <3.0 upper bound correctly excludes pyglet==3.0.dev2 (and any future 3.0 release) per PEP 440 pre-release ordering — verified that Version("3.0.dev2") < Version("3.0") holds and the specifier >=2.1.6,<3.0 rejects both.

This is consistent with the existing hf-xet>=1.4.1,<2.0.0 pattern in the same file, which was added for the same reason (a broken pre-release on NVIDIA Artifactory getting pulled in by --pre).

No inline comments — nothing to improve here. The change is correct and the scope is appropriate.

Minor note: Consider adding a CHANGELOG.rst entry under Fixed for source/isaaclab/docs/CHANGELOG.rst (e.g. "Fixed pyglet version pin to exclude incompatible 3.0 pre-release that breaks the Newton OpenGL viewer."). The contributing guide states every change should have a changelog entry, though I acknowledge dependency pins are borderline.