Respect NO_COLOR=1 environment variable #57

Describe the feature you'd like to request

When running a build with NO_COLOR=1, Vite does not put ANSI control sequences in the console output.

However, vite-plugin-image-optimizer does not yet honor this environment variable and generates colored output unconditionally. For example, this can be problematic when capturing the output in a log file. In my specific case, I'm trying to generate a GitHub PR comment containing the output from NO_COLOR=1 vite build, but the ANSI codes don't render correctly there.

Describe the solution you'd like

vite-plugin-image-optimizer should follow Vite's behavior and not produce colored output when the NO_COLOR=1 environment variable is set.

Since there already is an ansiColors configuration option, I imagine this should be an easy win.

Additional context

No response

Validations

• Read the docs.
• Check that there isn't already an issue that requests the same feature to avoid creating a duplicate.