Problem&Solution

## libstdc++.so.6: version `GLIBCXX_3.4.30' not found
```
Traceback (most recent call last):
  File "demo.py", line 92, in <module>
    pred_traj = run(cfg, args.network, args.imagedir, args.calib, args.stride, args.skip, args.viz, args.timeit, args.save_reconstruction)
  File "/home/postd/anaconda3/envs/persformer_dpvo/lib/python3.8/site-packages/torch/autograd/grad_mode.py", line 27, in decorate_context
    return func(*args, **kwargs)
  File "demo.py", line 45, in run
    slam = DPVO(cfg, network, ht=image.shape[1], wd=image.shape[2], viz=viz)
  File "/home/postd/data/luopengting/workspace/papers/DPVO/dpvo/dpvo.py", line 87, in __init__
    self.start_viewer()
  File "/home/postd/data/luopengting/workspace/papers/DPVO/dpvo/dpvo.py", line 118, in start_viewer
    from dpviewer import Viewer
  File "/home/postd/anaconda3/envs/persformer_dpvo/lib/python3.8/site-packages/dpviewer/__init__.py", line 1, in <module>
    from dpviewerx import Viewer
ImportError: /home/postd/anaconda3/envs/persformer_dpvo/bin/../lib/libstdc++.so.6: version `GLIBCXX_3.4.30' not found (required by /usr/local/lib/libpango_core.so)
```
### solution
```
conda install -c conda-forge libstdcxx-ng=12
```