Add new theme template

.github/ISSUE_TEMPLATE/new-theme.md

@@ -0,0 +1,38 @@
+---
+name: New theme
+about: Create a new theme for Whoogle
+title: "[THEME] <your theme name>"
+labels: theme
+assignees: benbusby
+
+---
+
+Use the following template to design your theme, replacing the blank spaces with the colors of your choice.
+
+```css
+:root {
+    /* LIGHT THEME COLORS */
+    --whoogle-logo: #______;
+    --whoogle-page-bg: #______;
+    --whoogle-element-bg: #______;
+    --whoogle-text: #______;
+    --whoogle-contrast-text: #______;
+    --whoogle-secondary-text: #______;
+    --whoogle-result-bg: #______;
+    --whoogle-result-title: #______;
+    --whoogle-result-url: #______;
+    --whoogle-result-visited: #______;
+
+    /* DARK THEME COLORS */
+    --whoogle-dark-logo: #______;
+    --whoogle-dark-page-bg: #______;
+    --whoogle-dark-element-bg: #______;
+    --whoogle-dark-text: #______;
+    --whoogle-dark-contrast-text: #______;
+    --whoogle-dark-secondary-text: #______;
+    --whoogle-dark-result-bg: #______;
+    --whoogle-dark-result-title: #______;
+    --whoogle-dark-result-url: #______;
+    --whoogle-dark-result-visited: #______;
+}
+```