AppData: Custom colors should have higher contrast

[Cassidy James Blaede]

Your custom colors are barely A-level contrast:

pinit/data/pinit.appdata.xml.in

Lines 80 to 81 in 748e0fb

 <value key="x-appcenter-color-primary">#007367</value> 
 <value key="x-appcenter-color-primary-text">#1a1a1a</value> 

When used in AppCenter, it's pretty hard to read some parts.

You can use Harvey to ensure your colors are at least AA level contrast.

[Ryo Nakano]

Thank you for your repotting, I fixed this in 9f0b20a. I chose these colors!

Really a nice app :)