YAML parsing "gotcha": version: 3.10 vs version: '3.10'

[atc0005]

From actions/setup-python#160 (comment):

Please pay attention that task input follow semver notation.

As for the confusing error message, it is a feature of YAML parsing. When you specify input like

version: 3.10

3.10 is parsed as a number and it is trimmed to 3.1 that looks like expected behavior for numbers. You should specify input with quotes to treat it as string.

version: '3.10'

The first and the second examples in README file shows the correct way with quotes. But looks like the third and fourth examples show incorrect way.