replace '.jpg' instead of 'jpg' to guarantee replacing file ending

[R-Fehler]

The Mapillary Vistas Dataset validation split contains random strings as filenames, one of which has 'jpg' as part of the random filename.

this results in a file not found error during validation when training with mapillary vistas dataset as a panoptic dataset

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Motivation

The Mapillary Vistas Dataset validation split contains random strings as filenames, one of which has 'jpg' as part of the random filename.

this results in a file not found error during validation when training with mapillary vistas dataset as a panoptic dataset

Modification

replace '.jpg' instead of 'jpg' with '.png'

BC-breaking (Optional)

no braking changes.

Use cases (Optional)

bug fix for widespread panoptic dataset: Mapillary Vistas Dataset.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMPreTrain.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[CLAassistant]

All committers have signed the CLA.