Fix Python dependency compatibility

[dellaert]

Why

GTDynamics currently requires numpy>=2.0.0 while accepting gtsam>=4.2. Those constraints are unnecessarily restrictive and can also be internally inconsistent: GTSAM 4.2 wheels were constrained to NumPy 1.x, while current GTSAM 4.3 supports both NumPy 1.x and 2.x.

This change:

• relaxes the NumPy requirement to the same supported lower bound used by current GTSAM, numpy>=1.11.0;
• raises the GTSAM requirement to gtsam>=4.3a0, avoiding the older 4.2 wheel line that was pinned below NumPy 2.

This lets pip retain a compatible NumPy 1.x installation instead of reporting a false conflict or forcing an unnecessary NumPy 2 upgrade.

Verification

• CMake configuration completed successfully.
• The native GTDynamics library compiled successfully.
• pip install --dry-run . resolved successfully with NumPy 1.26.4 and GTSAM 4.3a2.
• The Python test target could not start locally because the installed gtwrap is older than the latest GTDynamics wrapper template (KeyError: 'declaration_module_def'); this is unrelated to the dependency metadata change.

@kshaji3, could you please check out this branch locally and make sure the wrapper and test suite still work in your setup?

[kshaji3]

Reran all the installations in my local checkout, I have no issues.