Fix simple but annoying CI bug

[nyurik]

CI is currently failing with these 4 files:

Files tests/output/auto/mb_jpg.json and tests/expected/auto/mb_jpg.json differ
Files tests/output/auto/mb_png.json and tests/expected/auto/mb_png.json differ
Files tests/output/auto/pmt.json and tests/expected/auto/pmt.json differ
Files tests/output/auto/table_source.json and tests/expected/auto/table_source.json differ

The actual files can be downloaded here for the next week or so. The actual difference -- sometimes tilejson's bounds are rendered with an extra .0 at the end, and sometimes without. I have no idea why it passes fine on my laptop, and perhaps we may need to adjust insta to ignore trailing .0s... not sure what's the cause of this.