Use darker text color in dark mode

Author: marcphilipp

README.md

@@ -1,6 +1,6 @@
 <h1>
   <picture width="200">
-    <source media="(prefers-color-scheme: dark)" srcset="https://junit.org/assets/img/junit-logo-inverted.svg">
+    <source media="(prefers-color-scheme: dark)" srcset="https://junit.org/assets/img/junit-logo-inverted-darker.svg">
     <source media="(prefers-color-scheme: light)" srcset="https://junit.org/assets/img/junit-logo.svg">
     <img alt="JUnit" src="https://junit.org/assets/img/junit-logo.svg" width="200">
   </picture>