chore: Update .gitignore and robots.txt for improved site configuration (sitemap)

Author: LouisTier

.gitignore

@@ -10,4 +10,7 @@ Gemfile.lock
 assets/libs/
 node_modules/
 vendor
-.idea
+.idea
+
+# ! Previous in robots.txt
+# Sitemap: {{ site.baseurl | prepend: site.url }}/sitemap.xml

robots.txt

@@ -4,4 +4,4 @@ permalink: /robots.txt
 User-agent: *
 Disallow:
 
-Sitemap: {{ site.baseurl | prepend: site.url }}/sitemap.xml
+Sitemap: https://louistier.github.io/sitemap.xml