Update pull request template with checklist

Added confirmation checklist for theme submission requirements.

.github/pull_request_template.md

@@ -1,16 +1,3 @@
-After you have read the [instructions for adding a theme](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#adding-a-theme), please make sure:
+- [ ] Confirm that you have read and followed the [instructions for adding a theme](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#adding-a-theme).
+
 
-- [ ] your theme.toml [is complete](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#theme-configuration)
-    - name
-    - license
-    - licenselink
-    - description
-    - homepage
-    - demosite (if one exists)
-    - tags
-    - features
-    - authors/author (depending on whether the theme has multiple or a single author)
-    - original (if the theme is a fork)
-- [ ] you're using [absolute paths for images](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#use-absolute-paths-for-images) in your README
-- [ ] you've got [appropriate thumbnail and screenshot images](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#media)
-- [ ] your theme comes with an [appropriate license](https://github.com/gohugoio/hugoThemesSiteBuilder/blob/main/README.md#2-license)