Fix parsing of "calm wind"

[SkySails]

This PR fixes a small issue introduced earlier this year in #66

The METAR mentioned in this issue was KATW 022045Z 0000KT 10SM SCT120 00/M08 A2996, which contains an invalid "winds calm" value according to the Federal Meteorological Handbook:

d) Calm Wind. Calm wind shall be coded as "00000KT"
The first three zeros represent the wind direction and the last two zeros represent the speed.

Those changes to the regex prevented correct unit parsing for correct reports and introduced a bug where visibility values would be mistaken for wind speed.

This has been fixed upstream: mivek/python-metar-taf-parser#63

Fixes #79 , fixes #80

[aeharding]

Thanks for the PR! Looks like lint is failing though.

[SkySails]

Sorry, my bad (again). I ran yarn check-formatting and npm run check-formatting, but both returned the following result:

> metar-taf-parser@8.0.4 check-formatting
> prettier --check '**/*.{js,json,css,md,scss,tsx,ts}'

Checking formatting...
[error] No files matching the pattern were found: "'**/*.{js,json,css,md,scss,tsx,ts}'".
All matched files use Prettier code style!

I now tried npx prettier --check '**/*.{js,json,css,md,scss,tsx,ts}' instead of using the package script, and that did get me the correct warning! Should be fixed now.

[SkySails]

Seems like the problem went away as soon as I removed the single quotes from the pattern in that command. Perhaps it's an OS-specific issue?

[aeharding]

Looks good, thanks!