Installation stats graph visibility

Hi, just a minor thing i noticed about the visibility in the lines of the installation statistics graph is that some colors are hard to distinguish and others are barely visible.

From what it looks like, this snippet is what controls the colors:

packagist/js/charts.js

Lines 139 to 153 in 9e34e90

which evaluates to the following:

Unfortunately it's not possible to change these via external/injected CSS (the lines have an iterating CSS class, the other elements like legend and handle buttons don't), so this change has to be made in that script.

I can submit a little PR for that or leave it to you for the next time it gets an update. :)

	colors = [
	'#f28d1a',
	'#1765f4',
	'#ed1f96',
	'#ee1e23',
	'#b817f4',
	'#c4f516',
	'#804040',
	'#ff8040',
	'#008080',
	'#004080',
	'#8080ff',
	'#800040',
	'#800000',
	];