Make heatmap colors more distinct

Fixes: #13529

Author: silverwind

web_src/js/components/ActivityHeatmap.vue

@@ -28,10 +28,10 @@ export default {
     isLoading: true,
     colorRange: [
       'var(--color-secondary-alpha-70)',
+      'var(--color-primary-alpha-30)',
+      'var(--color-primary-alpha-40)',
       'var(--color-primary-alpha-60)',
-      'var(--color-primary-alpha-70)',
       'var(--color-primary-alpha-80)',
-      'var(--color-primary-alpha-90)',
       'var(--color-primary)',
     ],
     endDate: new Date(),